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Thursday, October 30, 2008

NYC preview and heatstroke wrap-up

A look ahead at the New York City Marathon

We've wrapped our heatstroke series now, thanks to everyone for questions, comments and stories. The series was quite technical, heavy on the calculations and concepts, but hopefully provided some food for thought, and the realization that heatstroke is not simply the result of exercising in hot conditions and failing to drink which is how it's often reported.

Today we look ahead at the final big city marathon of 2008, the New York Marathon, which takes place on Sunday. It features incredible fields, particularly on the women's side, and has Paula Radcliffe and Paul Tergat among its stars. One of them will win, the other will not! (we believe, anyway!)

The women's race: Radcliffe to win

Radcliffe is back after another disappointing Olympic Games, where she was hampered by insufficient training due to a stress fracture. She ran a brilliant 10-mile race in Portsmouth about two weeks ago, taking the lead from the gun and running at near world record pace in windy conditions. It was Radcliffe back to her old self, and so she looks a good bet for New York, provided she's done sufficient mileage to translate that speed into a good marathon (which I suspect is the case).

She'll be challenged by two very good racers in Catherine Ndereba and Gete Wami (to name but two of the potential winners). Wami has had a consistent, if not spectacular 2008. In fact, she's in contention for the overall prize of $500,000 as World Marathon Majors champion, winning it if she finishes second or better in New York (it will be her second title, testament to her consistency since 2007).

She finished third in London (after falling at a water table), having won Berlin in 2007, and come second (behind Radcliffe) in New York, only five weeks later. She did however bail from the Beijing Olympic marathon, citing stomach problems, and is looking for some solace in New York. Her form seems reasonable, a PB over 21km in the Great North Run, though that was followed by a hamstring injury, which may have affected her training.

That injury, plus the fact that Wami has seemed off the boil in recent races (problems like falling and stomach ailments tend to happen when you're not 100%) suggest that she'll have her work cut out to win NYC. Second might be possible, but honestly, if I had to stick my neck out, I'd say Wami will finish outside the top three.

So NYC 2008 is a rematch between Radcliffe and Wami, but this time, they're likely to be challenged by Catherine Ndereba, who is one of the all-time greats of marathon running. She was third in Beijing, and has a rich history of great performances. She's certainly one of the most consistent marathon runners around, and won the world title in Osaka in 2007. However, she's also been around for a long time, and I feel that she probably lacks that 1% that it takes to win against what is arguably one of the strongest fields in history. Three years ago, she'd have been a real challenger, but she hasn't won a big city race since 2005, and as pointed out by Letsrun.com, she's only won 2 out of 11 races this year. Her season already has an Olympic medal, and she's not in contention for the overall prize, so the stakes are a little lower as well. I pick her to run a solid race, and finish second, perhaps picking up the pieces in a race that is sure to be set up by Radcliffe.

Paula Radcliffe, then, is the odds-on favourite. She has the incentive to redeem a season beset by injury and a disappointing Olympic Games, and she clearly has the form, based on the Great South Run. When on form, she's the greatest runner in the world, by a substantial margin, so even allowing for being 2% underdone, she should still have what it takes. And she has found success in New York before, winning in 2004 and last year.

So I suspect Sunday will be a Radcliffe affair, and if she's anything near her best, she'll simply run a 2:22 pace from the gun, and knock the competition off, one by one. Seeing as how these predictions are guess-work at best, I may as well call it exactly!

I say Radcliffe takes the pace out from inside the first 10km, and runs through halfway in a shade inside 71 minutes. Because of the stakes, Wami goes with her, but gets dropped and then picked up by the more conservative racers like Ndereba. Radcliffe hangs on, slowing slightly in the second half, but wins in 2:22:09, for a course record. Second goes to a consistent Ndereba, about 2 minutes back, while third is taken by Rita Jeptoo of Kenya.

Fourth goes to a debutant Kara Goucher, who has one of the fastest times ever over the half marathon (66:57) and should be a formidable marathon runner one day. Wami, for her part, either finishes fifth, or decides to bail once she sees the World Majors title disappearing (depending on her contract - if part of her appearance fee depends on finishing, she'll finish. If not, she'll save herself for another day). And if this prediction is right, I'm heading to Vegas the week after the race while my luck is in!

Men's race: Tergat returns, but won't win

On the men's side, the field is not as strong, and is missing defending champion Martin Lel, and most of the top men, who've either called it a season after Beijing, or ran in Berlin a few weeks ago!

However, the race does feature a man who has come second, second and third in his previous Major City Marathons, Abderrahim Goumri of Morocco. On debut, he was beaten by Martin Lel in London (2007). Then last year in New York, Lel completely obliterated him in the final 400m, relegating him to second again. Then in London this year, he finished second, again behind Lel, though this time, Wanjiru split them.

Goumri must be delighted that Lel is not in New York, as the only constant in his marathon races to date is the sight of Lel disappearing with about 400m to go. That won't happen on Sunday, though a number of Kenyans may present some challenge. Goumri's last marathon outing was a disappointing one - 20th in Beijing, despite going in as one of the favourites thanks to his 2nd, 2nd, 3rd in three major marathons leading into it. He's run poorly at Championship marathons before - failed to finish World Champs in 2007, but that's more likely a function of his being quite poor in the heat. He bounced back from that to finish second in New York, and expect a similar revival this year.

One of the afore mentioned Kenyan challengers is Paul Tergat, who is back after 18-months away. Quite what sort of form he'll have is difficult to say. Tergat won the race in 2005, and enjoys New York, but I suspect he'll be short on speed come Sunday - he is 39 years old after all, and probably doesn't possess a 2:06 anymore. New York is not a 2:06 course, it's usually an attritional race and I believe Tergat, by virtue of his racing pedigree and the likely conservative pace will feature. However, to win is another matter. The field is relatively weak, other than Goumri (though there are a host of 2:06/2:07 runners, but none who have yet established themselves as marathon superstars), and Tergat will, despite his age, feature until the final reckoning on Sunday.

I'll be a little more circumspect on the predictions for the men's race, and rather go with the race preview done by Letsrun.com - they've listed the top 5, and I would not argue with it - it's the best race preview you'll find, well worth a read!

So Goumri to win, Tergat in second. Where I will deviate from the Letsrun guys is that I say third and fourth will also go to Kenyans, and maybe dos Santos will take fifth. As for a winning time, may as well put it out there - 2:09:30, with a faster second half than first - let's say second half in 64:25.

As always, we'll do our race report, featuring splits and race commentary, as it happens. So join us on Sunday, about an hour after the finish, and we'll give you low down on what happened on the streets of the Big Apple!


PS---We created a Science of Sport group on Facebook, so if you are logged on then be sure to join!

Wednesday, October 29, 2008

Heatstroke continued

Heatstroke part 3: Abnormal heat production, or failure of heat loss?

Yesterday, in our second post on heatstroke, we introduced the concept that the attainment of a body temeprature above 41 degrees celsius is NOT POSSIBLE due solely to environmental conditions, which is how you've probably always been told to think of it.

We explained how body temperature is a function of heat loss and heat production, and provided the potential for heat loss is greater than or equal to the heat production, there is zero chance of heat stroke occuring via purely "normal" physiological means. Therefore, when people do develop this condition, it is not as simple as saying "they didn't drink enough and the conditions were too hot", which was really the take-home message of yesterday's post.

We illustrated this with one example of heatstroke from the published literature, that of a man who hit a body temperature of 40.8 degrees after only 16 minutes of running when the temperature was 22 degrees celsius. There is no "normal" explanation for this, it must be pathology, which is where we continue this discussion today.

Eighteen cases, and not one makes physiological sense

Below is a table showing you 18 documented (that is, published in scientific journals) cases of heat stroke during exercise. There are undoubtedly others (we received two very interesting stories from readers - thank you for those - explaining their own adventures. One had a body temperature of 42 degrees (incredible), the other was at 40.5 degrees, but more on that a little later), but these are the documented cases.

I've highlighted three particularly interesting cases. You'll recognize the one in light green as the example of yesterday's post - a runner developed heatstroke after only 16 minutes of running when the temperature was only 22 degrees celsius, and the runner was only doing 4:30/km - hardly fast enough to overheat in any conditions, let alone the mild conditions, and certainly not in only 16 minutes.

The example in yellow is even more spectacular. This was a runner who collapsed after 16 minutes of a race when the temperature was only 17 degrees celsius. His body temperature was an incredible 42 degrees celsius, and most amazing of all, he was only at 7.4km/h. That is a pace of 8 min/km, which is either a very fast walk, or a very slow jog. I'm sure I don't need to emphasize just how spectacular a failure of physiology it is for this individual to overheat so quickly while exercising that slowly on that cool a day!

And then finally, the example highlighted red is a man who ran a half-marathon in air temperatures of only 4 degrees celsius, and made it to 88 minutes (he was on course for a 1:35 time), and his temperature was 41 degrees. I'm sure you can appreciate just how cold 4 degrees celsius is, and the next time you have to run in those conditions, ask yourself what the chances of overheating are, and you'll have an idea of why this particular case warrants attention!

The problem with heatstroke - a glitch in the balance

These are three cases that punch holes in the normal theory for heatstroke. There are others - 15 of them in fact in that table above, and numerous others, including the two cases we received yesterday from readers. Our approach to these 18 cases of heatstroke is to calculate two things:

  1. The heat production as a result of exercise. As we described yesterday, heat is produced thanks to muscle contraction, and we can work out this value with fair accuracy
  2. The heat loss through convective, radiative and evaporative means. Again, these concepts were explained yesterday
Now, the key to understanding heatstroke is to recognize that when heat loss potential is greater than heat production, the athlete SHOULD NOT develop heatstroke. I guess the analogy here is that if you are saving more money per month than you spend, you should not ever have to file for bankruptcy!

So let's take those 17 cases and simplify them to illustrate that heatstroke is very rarely a consequence of the environment. What we do is work out the ratio of heat production to heat loss.
  • If that ratio is equal to 1, then it means that heat production equals heat loss potential, and the athlete will be safe
  • If the ratio is greater than 1, then the athlete has a problem - they are producing MORE heat than they can lose, and therefore their body temperature will rise. They will thus either stop, slow down, or develop heatstroke
  • If the ratio is less than 1, then the athlete is safe - they are able to lose more heat than they produce, and so heat stroke should not happen
The graph below shows the result for 16 of the cases - 2 of them do not have precise weather data:

Clearly, every single one of these people had a potential for heat loss that exceeded the amount of heat they would produce from exercise. Therefore, these cases of heatstroke should never have happened, unless our equations are wrong (they aren't!), or unless something else, unaccounted for by the concepts, is causing the problem.

And therein lies the crux. These mathematical models for predicting heatstroke are clearly not "complete" for these individuals. The fact that these 16 runners and cyclists did develop heatstroke means that somewhere, either heat production or heat loss has been incorrectly accounted for. Broadly speaking, there are two possibilities:

1) Heat production is actually a lot higher than is calculated by the equations

This is not because the equations are wrong, because in 99.99% of people, they are relatively accurate, and certainly, the calculation for heat produced during exercise is well-established. However, in these people, something has gone wrong, and it may be that they have produced heat in large quantities from NON-EXERCISE related sources. In our recently published paper in Medicine and Science in Sports and Exercise, we called this "excessive endothermy", which basically means heat production from within.

Quite where this heat comes from is anyone's guess - perhaps the runner's efficiency is massively reduced for metabolic reasons? Perhaps there is a sudden increase in heat production thanks to unregulated opening of calcium channels? There is a condition known as malignant hyperthermia, where certain chemicals, most notably anesthetics, cause calcium channels in muscle to open. As this calcium is then transferred back into storage, it uses up a great deal of ATP and generates quite enormous quantities of heat.

The malignant hyperthermia linked has been looked at before - there are reviews on the topic. They distinguish between exertional heatstroke and malignant hyperthermia, but don't rule it out, mainly because when we look at people who suffer from heatstroke, they tend, in many cases, to be susceptible to malignant hyperthermia as well! In other words, there is likely a genetic link that predisposes people to these conditions. It has been suggested that heatstroke sufferers have a skeletal muscle abnormality that is similar to malignant hyperthermia.

Is it possible that exercise-induced heatstroke involves a similar "wasteful" use of energy in order to correct some kind of channel disruption? And what are the triggers? Interestingly enough, caffeine is one of the chemicals known to cause calcium channels to open, and so may actually warrant a closer look as a potential "trigger" for heat stroke. I must confess that I don't know the dosage that is required for this effect to exist. Other triggers may be central nervous system stimulants, like ephedrine (common in weight loss products), and the combined use of caffeine and ephedrine may be a real warning sign for this heat producing "spiral". This was in fact reported in Case 1 from the table above - a weight loss supplement contained both caffeine and ephedra.

There is a few other candidate "pathologies" - it may be that there is excessive sympathetic nervous system activation, triggered by a metabolic condition or muscle myopathy. Another possibility is illness - a bacterial infection before exercise may increase the chances of overheating, though this has never been confirmed (for obvious reasons), and relies mostly on retrospective analysis of specific cases (and not all cases either, it's worth noting).

Certainly, hot environmental conditions may be a trigger - we are not dismissing the role of the environment in all this, and it seems feasible that on a hot day, some "trigger" exists that may cause this same excessive endothermy to occur. The point we are making, however, is that the environment is merely the stage for the drama to be played out on - there is a pathlogical process at play here, and environment is not the CAUSE of heatstroke, merely a roleplayer.

A final illustration that heat production may be the cause comes from one case (case 3 above).

This person was admitted to the medical tent after the 56km Two Oceans Marathon with a temperature of 41 degrees celsius. He was placed in an ice-water bath, and wore a cooling vest. His body was then surrounded with ice-packs after that. It took TEN HOURS of cooling to get his body temperature down to normal levels! So how does the human body manage to keep its temperature above 38 degrees celsius when it's surrounded by ice-packs? The only answer can be excessive heat production, so great that it overwhelms the heat loss to the ice water and packs.

2) Heat loss is lower than the calculations suggest

Of course, the other option in these cases is that heat loss fails. If that were to happen, then our scale would tilt to the left, because evaporation and convection would suddenly fail to deal with the heat production (the ratio would then jump above 1).

Of the avenues for heat loss, the most likely to fail is evaporation, and this would of course occur as a result of a failure of sweating. This is difficult to prove, however, because often, people with heatstroke are sweating profusely, and so seems unlikely. Interesting studies of soldiers in Iraq suggests that it can happen when people are exposed to dry heat for a prolonged period (though this study dates back to 1932, and the methods for research may have been limited back then!)


However, it seems more likely that the problem is excessive heat production, and not reduced heat loss. Or, alternatively (to sit on the fence), it is possible that heatstroke is a generic term that actually describes a SYMPTOM, and not a condition. If this is true, then it could be caused by all of the above, or any one of them! There may be no single cause, in fact, it's highly unlikely. What does seem certain is that heatstroke is a failure of "normal physiology", because you do NOT develop this condition simply by running on a hot day and failing to drink enough water.

Therefore, the point of this series on heatstroke has been to debunk some of the myths surrounding the condition, and to explain that it occurs more as a result of a physiological failure than an environmental problem. And it is most definitely not the result of dehydration, which is unfortunately what most people attribute it to! Does anyone seriously believe that our three cases highlighted in the table above were dehydrated within 16 minutes of starting to run in moderate conditions, or after 85 minutes of running at near-zero conditions?

No, heatstroke is a very complex, difficult to predict and even more difficult to explain condition. But hopefully we haven't lost you in the maths of the series, and you now appreciate that heatstroke is pathology, not normal physiology, and does not happen simply because it's hot outside.

Thanks for the emails on your cases and experiences, by the way. We will pursue those further!


Tuesday, October 28, 2008

Heat stroke dissected

Heat stroke: A problem of physiology, not fluid or environment

Continuing on from our post two days ago, we are looking at heatstroke, a condition where the body temperature rises above 41 degrees celsius (this cut-off is somewhat arbitrary, it has to be said, at least in the exercise literature).

In that post, we introduced some of the paradoxes of heatstroke. The classic teaching on heatstroke is that body temperature rises excessively thanks to excess heat production which cannot be matched by heat loss. Heat production is thus a result of high exercise intensity, which means that this theory holds that you quite literally exercise yourself to death by generating so much heat that you overwhelm your body's capacity for heat loss. What it fails to account for is that humans usually slow down long before this limit is reached, or they stop exercise altogether once they hit a certain temperature, and so it's difficult to explain why they run themselves into heat stroke unless there is some "malfunction", which is where we're ultimately headed with all this.

Of course, the fluid-pundits climbed on board and advocated that the biggest problem would happen if you failed to drink enough water, because then your body temperature would rise even more rapidly and heat stroke would be a very real possibility. This particular post is not about the fluid-hyperthermia myth - we covered that in great detail in our series on dehydration, for those who are interested. Instead, we're interested in the physiology of body temperature regulation (and fluid, quite frankly, is barely involved).

It does get quite technical, but we'll do our best to speak logically, rather than mathematically! As a result, we will skim over the specifics of the equations, but I'd encourage you to check out this paper (which inspired this series, it was published earlier this year), where the equations are presented and discussed in more detail. As always, if you can't get the paper, drop us an email request and we'll send it along...!

Body temperature balance

The figure below is a (very) oversimplified schematic of the two halves of heat balance. It says that heat storage (which can be negative/heat loss), is equal to heat production minus heat loss. We can quite easily calculate and predict the two sides of the scale using mathematic formulae because we know what factors affect the heat production and heat loss components. These are convective, evaporative and radiative heat loss/heat production.

So for example, we know that heat production is a function of exercise intensity (cycling or running speed), body mass and a constant, which varies depending on whether you assume that the person has a high or low level of efficiency. The larger you are, and the faster you run, the more heat you will produce, which is why smaller runners have an advantage in hotter conditions. For example, the equation for an inefficient runner reads:

Heat Production (Watts) = mass x [(5.89 x speed) - 4.69]
On the right side, we have heat loss, which is largely influenced by the environment. Here, it's convection and evaporation that are mostly responsible, which is why air velocity and sweating are so important. Note that sweating by itself does not remove heat, only evaporation, which is why humidity is so vital - if sweat drips off, it does nothing for temperature, as our readers in the East and tropical regions will testify! (Also, note that body surface area, which is a function of mass and height. The larger the athlete, the greater their capacity to lose heat, but it doesn't quite manage to offset the fact that they also produce more heat)

Introducing the mathematical equations - conceptualizing the limits of exercise

Because we know how these factors interact and influence heat production and heat gain, it's possible to take that basic equation and refine it a little more. It now becomes:

Heat storage = Heat production - Convective heat loss/gain - radiative heat loss/gain - evaporative heat loss

Note that in all cases, the option exists to either gain heat or lose heat. For example, convective heat LOSS happens when the skin is warmer than the surrounding air, but as soon as the air becomes hotter than the skin (at about 35 degrees celsius), then convective heat loss falls to zero, and then eventually switches around - you start GAINING heat from the environment.

Now, we are in a position to make some interesting calculations regarding heat stroke, because we know that the body temperature will rise when heat is stored. And if we know how much heat is stored, we can calculate how much body temperature will rise. That is, we know that every 3.47 kJ per kilogram will raise body temperature by 1 degree celsius, and so if a man weighing 80 kg gains 278 kJ in one hour, his temperature will increase by one degree celsius in that time. To extend this further, if he wants to run into heat stroke, he'd have to raise his temperature by 4 degrees celsius, which would require him to store 1111 kJ.

So the approach we can now take is the following:
  • We can calculate the rate of heat production (thanks to knowing the running speed and mass of the person);
  • We can calculate the rate of convective cooling if we know the air temperature
  • We can calculate the rate of radiative heat gain if we know cloud cover
  • We can calculate the maximum capacity for evaporative heat loss if we know the humidity
These four variables are all we need to be able to say whether the possibility of heat stroke exists, because:
  • If the capacity for heat loss is greater than the calculated heat gain, then heat stroke is not possible (mathematically, anyway. More on this a little later)
  • If the capacity for heat loss is lower than the calculated heat gain, then our scale tilts towards heat storage, and the result is that our athlete will gain heat, his temperature will rise, and in theory, heat stroke is possible.
Example: Why heatstroke is not an environmental problem

This is best illustrated with an example:

Note that we're making "worst case scenarios" here - we assume he's inefficient, that there is no wind other than the wind he generates by running and that he is also running on a bright sunny day. We do this to make a point - by taking the "extremes", we want to see just how bad things need to be in order for him to develop heat stroke.

So, our calculations reveal the following:

To empahsize this further, we can work out that for our runner to keep his body temperature EXACTLY the same, he would have to evaporate 1.5 L of sweat per hour. But our calculations also reveal that it would be POSSIBLE to evaporate 1.6 L of sweat per hour. This means that he has no problem losing the heat he produces, and should NOT develop heatstroke (once again, for more detail on the calculations, refer to this paper)

Here's the catch: He did get heatstroke, in only 16 minutes!

Ah, but now, what if I told you that this man is one of the 18 cases reported in the literature. In fact, this runner, running in these conditions, was pulled out of the race after ONLY 16 minutes, with a rectal temperature of 40.8 degrees celsius! Therefore, despite the fact that there were no limitations in the environment, and the fact that he COULD have lost all the heat he produced, he failed. And the result was that he developed heat stroke after less than 4km of running!

If that does not strike you as extra-ordinary, nothing will. Your first thought might be that our maths is dodgy (and you have a reasonable case, as I'll explain at the bottom of the post), but really, consider those conditions: 22 degrees, and the humidity was high, sure, but they're not difficult running conditions. If you stood on the start line of a 10km race in those conditions, the thought of heat stroke would not cross your mind. How about after 16 minutes? You should be thinking that something serious went wrong with this runner. And you'd be right. The problem is that we don't quite know what it is!

Some pointed questions about heatstroke

In the interests of time, we'll tackle that question in the next post in this series. But what I want to leave you with are the following questions, which will hopefully give you reason to challenge what you know about heatstroke:
  1. If heatstroke is purely due to the environmental conditions, then why is it so rare? In SA, for example, we have a cycle race with about 30,000 participants per year, and only 5 cases in the last 6 years have been reported. That's 1 in 30,000. And the prevalence seems about that low. Now, consider that 29,999 people will be exposed to the SAME conditions, and NOT develop heatstroke, and suddenly you realise that the environment is NOT the crucial variable. Obviously, it contributes, as we've shown above, but it's not the driver. Something else is...
  2. Heatstroke cannot simply be a function of exercising so hard that you overwhelm your body's capacity for heat loss. The cases we showed in yesterday's post are representative of this, and that's what I'll write about tomorrow. But the point is, as we saw in the example above, heatstroke occurs even when the theoretical limit doesn't exist. It's not a function of heat production through any normal means.
  3. Third, why is heatstroke more common in back-of-the-pack runners? According to every theory, heatstroke should be most likely in faster runners (especially larger ones). Yet this is not consistent with what is observed. We had an email from someone who is involved with the marines (which is where heatstroke does seem to occur, though it's rarely documented in scientific journals), and I dare say (with respect to the marines), they're not exactly exercising that hard when they develop heat stroke. So something else must go wrong.
In conclusion, heat stroke doesn't seem to be driven by the environment, though it's a contributing factor. It's also not explainable by the athlete's "high" workrate, because they are rarely actually producing that much heat. So the quest begins for the answer. Join us next time!



I've made use of mathematical equations in this post to illustrate the concepts. That's certainly a point of contention, because the human body is more complex than an Excel spreadsheet. So I don't mean to oversimplify or rely too heavily on the maths and calculations. However, what these equations do allow is a demonstration of the conceptual issues around heatstroke. We assume the worst (no wind, direct sun, poor efficiency) and then show that despite everything being "worst case", the capacity for heat loss exceeds heat gain. The equations are therefore useful to demonstrates concepts.

Where they would fail is if we tried to use them predictively or prescriptively. In other words, we can't say definitively that a 60kg man running at 15km/hour at 25 degrees with humidty of 60% will have a body temperature of 39 degrees after 45 minutes. That would be reckless use of the tool. So please, understand that we've illustrated concepts here, and hopefully made a strong point that the environment is rarely a key, and that actually developing heat stroke is extremely difficult according to "normal physiology".

We'll pick up on this point again tomorrow.



For those who feel like sinking their teeth into the cases and the equations a little more, check out:

Rae, Knobel, Mann, Swart, Tucker and Noakes. Med Sci Sports Exerc, 40: 1193 - 1204, 2008

Saturday, October 25, 2008

Heatstroke: Some interesting observations

Heatstroke: The reality doesn't fit with the perception

One of the more interesting ways in which we can study physiology (especially during exercise), is to observe it when it fails. Take for example the Calvin and Hobbes equivalent of "failure physiology":

Calvin (the young boy, for those who haven't discovered Calvin and Hobbes) asks his father a seemingly simple question, and gets an absurd answer. Yet incredibly, this is how exercise scientists have approached certain problems for many years - fatigue and temperature is the most obvious of them! So we study what happens at failure (exhaustion) and then infer the cause backwards from there! For example, when studying fatigue, many exercise physiology studies make runners or cyclists exercise at a fixed workload until they are absolutely exhausted and then measure things at the point at which they stop, assuming them to be the cause.

"We happened to notice that the runners all stopped when they had low glycogen levels/high body temperature/high lactate levels. Therefore, they stopped because of it!" is the logic applied (we covered this in our fatigue series earlier this year).

When the body overheats (i.e. heatstroke), it's the classic illustration of this "load limit" concept for humans during exercise. We know from these "run until you drop" studies that humans almost always stop exercise when their body temperature hits 40 degrees. This has been called the "critical limiting temperature" (Calvin's dad would be proud), and the theory was that muscle activation fails at this point. It was subsequently shown that if you allow the athlete to choose their own speed (like you do in every exercise situation), they slow down long before they overheat - we called this Anticipatory Regulation of exercise by the brain.

The problem with this theory - physiology does fail

This anticipatory theory, and even the "load-limit" theory, do pose some problems for us, however, because they imply that humans will never exercise so hard that they drive their body temperature to even higher levels. Recall that heatstroke is defined as an increase in body temperature above 41 degrees celsius (or 104F), which would be very difficult to explain if your brain "fails" at 40 degrees, or regulates you so that you never get there.

Of course, you may argue that some people can "over-ride" this physiological regulation, but I would argue that this is akin to suggesting that someone can commit suicide by holding their breath. It doesn't matter how badly you want it, but physiology always wins the day! I will concede that some people have exceptional "mental toughness" and approach the limit much more than others, but no one breaks right through it. And now, consider that heatstroke very rarely happens in the elite athletes, who would surely be the ones most likely to have this "mental override" capacity. So it seems an oversimplification to say that heatstroke happens because people "push themselves" too hard in the heat.

Similarly, when you actually look at cases of heatstroke, something even more intriguing jumps out at you - heatstroke has almost never been reported on hot days! Look at the following table, which shows 18 documented cases of heatstroke.

Hopefully, you'll be struck by the relatively low temperatures at which many of them have occurred. There are races, for example (cases 3 to 9), where temperatures are below 20 degrees, sometimes only 4 degrees celsius! That should set off an alarm in your mind about how heatstroke occurs - is it simply a case of exercising in the heat until you overheat? It seems more complex than this. And what I'll do in our next post is look specifically at two or three of these cases and show how it's physiologically "impossible" to explain these cases according the classic physiology that you run yourself into trouble. Basically, it's impossible to run fast enough to develop heatstroke unless you're very heavy and run very fast...(but more on that in the next post of this short heatstroke series)

Diagnosing heatstroke

These 18 cases are among the ONLY documented cases of heatstroke, which is itself incredible. You probably think that heatstroke is very common, because every time there's a race in vaguely hot conditions, you're warned to drink lots of fluid and take every precaution to avoid heatstroke (especially in the USA, I must say. That's a fact). But incredibly, exercise science and sports medicine often even fail to measure that load limit before they attribute just about any "failure" in the heat to heatstroke! So, returning again to the definition (a body temperature that exceeds 41 degrees celsius), you'd be amazed at how often heatstroke is "diagnosed" without ever measuring the body temperature. Instead, the default response to a case where an athlete can't exercise and it happens to be a relatively warm day outside is "heatstroke" regardless of what the person's body temperature is.

So I must stress that there is a big difference between heatstroke and what one might term "exercise intolerance due to feeling terrible in unaccustomed heat," which is what I think accounts for most of the problems people experience during running. And in our discussion of the Chicago Marathon, it was mildly amusing to read some responses that were indignant at my suggestion that some people expected marathons to be "easy", whereas others (those in the more demanding climates around the world and thus used to the heat) have a completely different view of running in different conditions. In some places, a marathon at 24 degrees with moderate humidity is a pleasure. For others, it's a cauldron of heat and danger...!

The physiological abnormality of exercise

Returning to the heat issue, what may surprise you is that during exercise, almost regardless of the air temperature, humidity and windspeed, your body temperature will regularly hit about 39 degrees celsius, with no ill effects whatsoever - it's a controlled "hyperthermia", and you're halfway to heat stroke without ever even realising it! It's actually amazing to consider how exercise makes the "abnormal" feel normal. Take a physiological snapshot of yourself during a 10-mile tempo run and your heart rate is 175 beats per minute, your breathing rate 54 breaths per minute, your body temperature is 39 degrees celsius. A doctor presented with those statistics would likely admit you to an ICU, yet you feel absolutely perfect during exercise!

The point is that the perceptions you have of your own physiology are strongly influenced by set-points. That is, your brain can adjust what is "acceptable", the set-points, to create a context to interpret incoming physiological signals. Think, for example, of when you have a fever - you are shivering even though your body temperature is 39 degrees celsius and you've overheating. That's because your body's set-point has been reset and you are kicking in heat GAIN mechanisms even though you're hot - how you FEEL is not necessarily the same as how you are ARE. A similar concept applies to exercise.

And the point of all this is to introduce the issue of heatstroke to you. Your body is a remarkably designed machine, capable of losing far more heat than you might realise. Yet it CHOOSES to allow you to gain heat and you become "hyperthermic" during exercise even on cold days. Where this is leading me is to the next post on heat stroke, where I'll look at the physiology of heat gain and heat loss and explain how actually running yourself into overheating is a pretty tall order. Instead, there is something else that accounts for heat stroke, and we'll put forward a few suggestions about what it might be.

Join us then.


Wednesday, October 15, 2008

Chicago Marathon 2008

The data do not lie: The actual environmental conditions from the course

Apologies for the absence lately, it has been a hectic time at work and for other endeavors lately, but our deadlines have now passed and we can return to a more regular posting routine that we are accustomed to. Just in time, too, as the NYC Marathon is just over two weeks away, so watch for our previews of that one as Paul Tergat and Paula Radcliffe try to add to their previous victories in that race.

But for now let's look back to the Chicago Marathon, where much was said about the weather conditions on the day. All the fuss was due to last year's oppressive conditions which forced the organizers to close the course early and send people back to the finish. It was a cooking day in Chitown last year, to be sure, but this year it was a stunning day---and we have the data to prove it!

The historical record

A look at the past three runnings of the race reveal three vastly different days. In 2006 it was a miserable day---cold, in the 30s or 40s F, if I recall, and overcast the entire time. Generally a dreadful day to run a marathon! 2007 was quite literally burned into our memories - it was already in the 70s F at the start, with no wind, and glaring sun that baked an already hot city into the 90s F by day's end.

This year was cooler at the start, and much less humid as the day went on, producing a warm but dry day. Here is how the conditions stacked up from last year and this year, according to the data from the weather website Weather Underground:

These graphs show the "official" historical data on the Weather Underground site. Temperature data are on top, while relative humidity data are at the bottom. We took values from the same station, so there is no bias in that sense. The big difference is the starting temperature---it was over 10 F lower this year, and so even though the humidity was similar at the start I can tell you it was a vastly different day. And from 11:00 the humidity was consistently 10% lower than last year.

This year's weather was something runners know about. It was one of those days where you step outside in your running kit and think, "Hmmm. . .maybe I should bring a long-sleeved shirt with me to the start because I might get cold standing around before the gun." Last year, on the other hand, was muggy, hot, and oppressive. The preceding month was unusually warm for fall in Chicago, and every morning was hot and humid even before the sun came up. You never felt cool last year in September during your morning run or ride, I can tell you that much.

The "official" vs. the "actual"

But the official data tell only half the story, and after last year the race organizers knew they needed something more to inform them about the conditions on the course. The problem last year was that around 11:00 it was clear to the officials that they were going to have problems if they kept the course open as their "peripheral" resources, i.e. ambulances on the course, were all deployed and transporting runners to local hospitals. Therefore it was the best decision they could have made to close the course, because had anything else happened they would not have been able to respond to it.

Part of the solution was to invest in technology and purchase four portable devices to measure the temperature and relative humidity on the course, rather than relying on the data from weather stations. We placed these devices (together with faithful graduate students!) at strategic points on the course, namely the northern-most, western-most, and southern-most points and the finish area. Then we took readings every 15 min, although for simplicity we have included only hourly measurements here:

Again, temperature data is on top and humidity data at the bottom.

The first noticeable detail is the the readings we took on the course are quite different from the "official" data. This might not be a surprise as that weather station is likely distant to the race course, and weather is a very local phenomena. But still, as far as we know this is the first this this kind of discrepancy has been shown, and the important implication is that if you organize an event and want to know what is happening on your course, you must collect the data yourself and analyze in real time to see how things are changing and exactly what is happening.

During portions of the race the difference between the "official" values and the data we measured was as much as 40% for the humidity and 11 F for the temperature. In addition, the difference between the northern-most station, located near mile eight, and the finish was 6-7 F. The reason is probably because that part of Chicago, the neighborhood of Lakeview, consists of heavily shaded narrow streets. Compared that to the finish in Grant Park, which is totally exposed to the sun, especially for the first half of the day as it is eastern border is Lake Michigan.

So based on the data, one has to ask, "Why not run the course in the opposite direction?" After all, temps in Lakeview were 5 F lower when we stopped collecting data at 11:00 there! Of course we did not measure into the afternoon, and by then the temps on the northside might have been similar to the finish. But this is a good example of how science and data can drive critical decisions that might improve future events.

Was the weather a factor?

This question is being debated in the comments section for the race report, and we have people weighing in on both sides. Was it hot? Yes, it was, and the air temperature was close to what it was last year, in fact. The humidity was much lower, though, and the real difference was probably the starting temperature and the fact that the weeks prior to the race this year were generally much cooler. Overnight lows have been solidly in the 50s F since the beginning of September, and so the city never really heated up like it did last year.

The conditions were far from "ideal," but then again they were not dreadful by any stretch. It was a stunning day in Chicago, and normally wuhen the environmental conditions are considered "hot," it shows in the winning time. Evans Cheruiyot's 2:06:25 was incredibly fast, and not indicative of a winning time in "hot" conditions. That said, the conditions were not ideal for world record-type performances. On the day, in 'real-time', we wrote somewhat arbitrarily that the elites were probably slowed by about a minute as a result of the temperature, which seems reasonable, even now.

The early pace in the elite race was too fast, given the conditions. They paid for it in the second half, with the exception of Cheruiyot (who did also slow down, it has to be said), and large time gaps were the result of the super fast early pace, combined with the conditions. However, for the vast majority of the field, the conditions were not harmful, and the athletes running anything slower than...oh, about 2:08, were never, ever in danger of heating up too much, or becoming critically dehydrated.

The medical tent

I was sitting at the entrance to the medical tent, and in time we will analyze the data regarding symptoms, number of admissions, time to discharge, etc. One anecdote I can share now, though, is about a runner who must have run about a 3:15 or so, judging by what time he came to the tent. He was on the back of one of the golf carts used to get collapsed runners from the finish to the tent, and was sitting up with a Gatorade cup in his hand. As he passed us, he recoiled and spewed what must have been a beaker full of vomit. That in itself was not remarkable, but the volume was---the poor guy must have puked 500+ mL of Gatorade/water! Yet there he was, trying to drink MORE, probably because he'd been told he felt so terrible as a result of dehydration! Dehydrated, with maybe a liter of fluid sitting in his stomach... if something doesn't strike you as being "wrong" with that picture, then nothing will He had no business with that kind of volume in his stomach, and in case you missed it last year you should read our series on dehydration and fluid intake. Just click the "Featured Series" tab above for the links.

In the meantime feel free to weigh in, especially if you ran the race, and watch for more data from the medical tent as we analyze that!


Tuesday, October 14, 2008

SA sport commentary

South African sport: Where winning doesn't matter, and we are the losers

A very South African-centric post today, apologies to our readership in the USA and the rest of the world. Feel free to read and weigh in with your opinions (just keep them tidy!), because it might be interesting to hear what you think of how sport in my country (SA) is run. To provide a little bit of background, South Africa had their worst Olympic performance since 1936 in Beijing, and also find themselves sliding rapidly down the ladder of world sport - many of our teams are now languishing outside the top 10 in Africa, which, for it's wealthiest nation, is a dismal under-performance.

In response to that decline, and other problems associated with SA sport, a big meeting was held to chart the way forward for SA sport. However, instead of developing solutions (and listening to them, because those solutions exists and have been proposed), the only thing that emerged was a political movement for getting rid of the Springbok logo of our national rugby team. If you think that's crazy, you're right. You may be reading that and thinking "what's the big deal?. It's just an emblem." Well, it gets complicated, thanks to our checkered past and the racism that surrounded the logo in years gone by. But that's not what this post is about, and my opinion on the emblem is largely irrelevant. What I would like to discuss is just why SA sport finds itself in the situation it does - the arguments about the Springbok logo point to the solution. This article first appeared on Health24.

Politics and sport

Last week South African sport was once again dragged into political controversy when the National Sports Indaba in Durban produced only one major outcome – a request for the removal of the Springbok emblem as a result of its “racist” connotations.

The Sports Indaba was supposed to contribute to clearing up some of the problems in South African sport; instead, this outcome has reignited a debate that creates a new set of problems. The real problems remain unsolved, relegated to the periphery by political posturing and non-performance-based agendas that are focused on anything but winning.

The sports indaba was called by the Minister of Sport with the intention of charting the way forward for SA sport. This was partly in response to our poor performance in Beijing, and other problems that have been affecting South African sport of late. Soccer is primary among them, but there are also issues around sponsorship across the minor sports; and the development of sport among women and disability groups was also on the agenda.

As is always the case when politics meets sport in South Africa, perhaps the biggest focus was reserved for transformation policies. There is nothing wrong with this, of course, and the appropriate strategy to address transformation is an important piece of the overall sporting puzzle. However, the Indaba was intended, I believed, to be a meeting to discuss how we might improve on-field performances through mechanisms like coaching, sports science, and yes, transformation.

It’s black and white

Pardon the expression, but winning in sport really is a black and white issue. You are either doing what you can to win, or you will lose. Sport makes little allowance for distractions from the process that aims to ensure success. Progress is measured in milliseconds, and margins for victory are so small, so hard to find, that experts and athletes will spend years searching for them. If you fail to devote 100% of your energy to joining the quest for those milliseconds, then you lose. You are either a prospective winner or a guaranteed loser.

It is against this backdrop that we have to consider South Africa’s sporting report-card in recent years.

  • Consider that South Africa was once ranked inside the top 20 of world soccer, and now languishes in 85th position.
  • Consider that our netball team was a world championship silver medalist in 1995 and is no longer even the best team in Africa.
  • Sports where South Africa has a rich history and legacy of champions, like boxing and athletics, are now failing to produce new competitors, let alone champions.
  • And then of course, there was Beijing 2008 – South Africa’s worst performance since 1936, with a solitary silver medal the product of many years of sporting neglect.

So an overall “health check” of SA sport will reveal a very dark, ominous picture – little is positive, most sports are declining and a diagnosis of “critical” or “terminal” would apply to most.

Yet a possible solution exists, driven by people who possess both the desire and the ability to improve our on-field performances. I was privileged to attend a conference in Sports Medicine in Cape Town last week, at which many of the doctors and physiotherapists associated with the SA Olympic and Paralympic teams were present. It’s immediately obvious that expertise is not the problem in South Africa – consider, for example, that when Great Britain decided to invest heavily in sports medicine for their Olympic athletes, they identified two South African doctors as world leaders, and then drafted them in to help with their efforts. South Africa possesses experts in abundance, and they are the solution for South African sport.

Unfortunately, South African sporting authorities fail to recognise this, allowing other nations to recruit our talent and intellect, and then use it against our athletes. Our own sporting codes and government instead rely on the volunteer efforts of those people who can do a job, but are not empowered to do so.

I had, for a long time, not understood why this situation has been allowed to develop, why expertise is not prioritised. But the outcomes of the Sports Indaba reveal the possible reasons – politics overrides excellence. Those in authority barely acknowledged expertise-based plans, focusing instead on fighting battles against the past, and the emblem of only one of our sports teams. Discussions around the real challenges are destined to grind to a halt under the weight of the political incentives.

The root problem

The single biggest problem we face is that the people who run SA sport are not incentivised to win. By virtue of the fact that sport separates people out into those who aim to win and those who will lose, the implication is that South African sport is tainted by losers, who do not care about winning. It's as simple as that. Those in authority are more interested in their political agendas than they are in winning. So ‘transformation’ hijacks every single discussion, every attempt to chart a path forward for SA sport. The actual solutions to on-field performance then become about as significant as a drop of water when it falls into an ocean.

When so much energy is invested into political agendas, and incentives that do not contribute to winning, we lose. This is the reason our athletes are not likely to escape from the doldrums – no one is offering the hand of high-performance support.

The role of transformation

Transformation is critical to high performance success. Why? Because sports performance is like farming: you find yourself some arable land, you plant the seeds, you water them, provide fertiliser and then hopefully, with the right conditions, you produce a good crop that year. In South Africa, we are using only 20% of our arable land. That is why transformation is vital. If we fail to access all the talent that has until now been marginalised by political, economic and social ideologies, we will never achieve our sporting potential – why pick a squad of world class athletes from only 15% of the population?

The problem, however, is the time-scale, and that's where people have missed the point. Firstly, if you force athletes into top-level sport with selection criteria based on colour and not on merit, you produce two very destructive outcomes in two very different groups of people:

The first is a sense of entitlement. You are sending a signal to certain groups of people that they are going to be supported, regardless of the effort they put in. So you don’t get the necessary work ethic, drive and competitive passion; it’s part of the reason South Africa produces so many excellent junior athletes and sports people, but so few go on to achieve senior success. Entitlement is destructive to success, because it dilutes dedication and commitment to training.

The second outcome is disillusionment in the non-selected population. South Africa cannot afford to marginalise existing talent in an attempt to find new talent, and this is what quota systems achieve. Can you imagine a coach or manager standing before a young school team and telling them that the secret to success is to be disciplined, to work hard, to train with commitment and success will be the result? Quota systems make a mockery of that advice, because the overt message is that work ethic and discipline are only part of the process.

A culture of sport

And then finally, what I believe people have missed is that sport is a culture. Australia has a great cricket team because in the 1920s, it built a culture through great players such as Bradman. Jamaica has great sprinters, because there is a culture of sprinting on the island. Kenya is a great producer of long-distance athletes thanks to the efforts of those in the 1960s who laid a platform that extends to today.

In South Africa, we have a culture of rugby – as a function of the past, mostly amongst whites. That can (and should) be changed, is changing, but not overnight. It will take at least three generations to change the culture. The first is the generation of people who have been discriminated against. It’s painfully regrettable that they have had little opportunity to achieve success in rugby.

The second generation is their children, who should be exposed to a more balanced world view, and begin to adopt the attitude of performance-based success (as opposed to quotas). I have very little doubt that if you went to a strong sporting high school today and asked the typical 16-year old what he felt about quotas, he would tell you that he would much rather achieve success based on the work he puts in. That is a sign of things changing for the better. And finally, their children's children will enter a sporting environment where the parents and grandparents are equally exposed to the culture that it takes to create sporting champions at a young age.

I must emphasise that the same principle applies to those running the sport – I have no doubt that there are still issues of marginalisation and discrimination in certain sports, and these should be policed and removed. Over time, however, the stereotypes that exist from the top and from the bottom will evolve until we reach a point where success is a function of work and talent, which is how it should be.

So transformation then, should be seen as a long-term process, because achieving sporting success is a long-term venture. It begins from the top, however, and I reiterate that South African sport has failed to win because it is led by people who are not winners. They do not prioritise excellence, they have little interest in intellect and expertise, and they are leading South African sport into an increasingly hopeless situation.


So we therefore need to make a decision – do we wish to be a nation of world-beaters, excellent sportsmen and women, who strive to find the milliseconds it takes to win? Or do we wish to allow these other, non-winning related agendas to override that pursuit. If we choose the former, we must recognise that our preoccupation with transformation is strangling our efforts to achieve a winning sporting nation.

To return to the medical health-check analogy, South African sport has a cancer, and like any cancer, it can be treated through the removal of the responsible cells. For success, that is crucial.


Sunday, October 12, 2008

Chicago 2008: Race Report and splits

Chicago 2008: Evans Cheruiyot and Lidiya Grigoryeva win in fine style

The 2008 Chicago Marathon champions are Evans Cheruiyot and Lidiya Grigoryeva. In two very different races, the Kenyan and Russian triumphed in times of 2:06:25 and 2:27:17, respectively.

For Cheruiyot, it is the first major marathon win of a career that promises to deliver great performances. For Grigoryeva, it's the latest in a series of big wins that includes the Boston Marathon in 2007, Los Angeles and the Paris Marathon.

Below is our report from both races, and splits from the men's race.

Men's race report

The early pace was fast and consistent - sub 3 minute kilometers pretty much from the gun, all the way to halfway, and remarkably, a relatively strong field had been strung out to three by the half-way mark. The temperatures were relatively high - not quite Beijing-like, but then the depth of the field was not the same either. What the commentators failed to mention was that the humidity was quite low in Chicago, which is the big difference from Beijing.

The pace-makers were not up to the job - they were gone within 17 km, and it was Emmanuel Mutai of Kenya, one of the pre-race favourites and a 2:06:15 runner in London earlier this year, driving the pace. The shots from the bike along the route showed very clearly just how aggressive the front running was - it was as though the top Kenyans have all adopted the Sammy Wanjiru-Martin Lel tactics from Beijing - drive as hard as possible at the front, and see who survives!

Evans Cheruiyot was always going to be the biggest danger - the fastest half marathon runner in the field, and we are very firm believers that the short distance speed is THE big predictor of marathon performance. He came third at the world half marathon championships in 2007, running 59:05, and has subsequently run 59-minutes twice, which is a sign of things to come.

The halfway mark was reached in 62:27, which is incredible given that it was being driven by only Mutai, and not the pacemakers. About 25 km into the race, Cheruiyot moved into the lead, running side by side with David Mandago, who was the big surprise package in the race. Mutai was first to go off the back, a gap of 10m created at the 27km mark. That left Cheruiyot and Mandago to slug it out over the final 15km.

The pace was slowing ever so slightly, projecting a finish of 2:05:20 by the 30km mark. The mile pace from 32km to 38km was consistently around 4:50 (or 3:00/km). At 35km, Mandago surged on what must Chicago's steepest hill - a bridge over a highway, and Cheruiyot was momentarily gapped, but held on about 2 strides back. Mandago then surged again, and the gap was 4 strides, Cheruiyot on the ropes but still on his feet.

The knock-out blow did not come, and Cheruiyot was to recover and return to Mandago's shoulder with about 5km to go. Then with 3km to go, Cheruiyot delivered the knock-out blow, opening up a lead of 50m in quick time. Mandago's effort had expired, and it was the faster half-marathon runner who was finally clear and on his way to a relatively unchallenged win over the final 2km. At almost exactly the same time, the women's race saw its decisive move (see report below), which meant that last year's dramatic sprint finishes would not be repeated this year.

Cheruiyot went on to finish in 2:06:25, a huge PB and an "arrival" on the major marathon circuit and surely the start of a great marathon career, given his half marathon credentials. He vindicates the confidence shown in him by the Letsrun.com guys, who picked him to win this race. Second went to Mandago, a great run for him just over one minute back, and third was taken by Timothy Cherigat in 2:11:39.

Below are the splits from the men's race, showing just how aggressive the early pace was, particularly the section from 15km to 20km. However, it also shows the attrition in the second half, where the pace just got slower and slower towards the end.

Women's race

The women's race took on a pretty similar feel to the Beijing Olympic Marathon. The early pace was very slow, projecting a 2:34 time, and the group was understandably large. No one was really forcing the pace, though the Olympic champ Constantina Tomescu Dita was showing at the front quite consistently. She was just there, however, not really doing anything to the pace. The first 10km was super slow, it picked up a little in the next 10 and the halfway mark was reached in 1:16:04.

Just after halfway, the race was suddenly shaken up, just as it was in Beijing, though on this occasion it was not Dita, but two Russians, Lydiya Grigoriyeva and Alevtina Biktimirova, and an Ethiopian, Bezunesh Bekele, the Letsrun.com pick as race winner, hanging on about 3 strides back, who made the move forward.

Then, somewhat surprisingly, Bekele dropped off, which meant that Grigoryeva and Biktimirova, two almost unmentioned runners in the previews, had the streets of Chicago to themselves. Biktimirova was second in Boston earlier this year, beaten in that fantastic sprint with Dire Tune of Ethiopia.

Grigoryeva and Biktimirova are apparently the best of enemies, and live and train in the same town but don't speak to one another. So the race had something of a "personality" to it, and Biktimirova was doing the work out in front, though gesturing to Grigoryeva to give her some assistance. It was very surprising that they were able to create such a large gap so quickly. The rest of a relatively strong field was almost instantly blown away, and I was amazed at how the race was transformed into a two-woman show so rapidly.
Grigoryeva eventually took control, using her pedigreed speed to move into the lead and then open up a large gap at about the 32 km mark. The remainder of the race was something of a procession, the biggest surprise being the size of the time gaps and the relative "ease" of the victory.

For Biktimirova, the final results will have a feel of deja vu about them. In Boston earlier this year, she came second, and the men's race was won by a Cheruiyot - on that occasion, it was Robert Cheruiyot, one of the stars of the marathon running world. Today, the men's race was won by a future star of the marathon world in Evans Cheruiyot.

The weather - last word

It was another relatively warm day in Chicago. Not as bad as last year, but it's not Berlin, that's for sure. The temperatures on the start line were being reported as 60F, or about 16 Celsius, and peaked in the 80s (25 Celsius) by the time the elite men finished. If you're reading that and thinking "big deal", then we're right there with you - it's not that bad. But because of last year's dramatic events in Chicago, and because the public in the USA have been led to believe that marathon running should be easy, everyone was on high alert.

The commentators were very poor regarding the heat - they kept going on about the "very similar conditions" between Beijing and Chicago, when in fact the stats will reveal quite a different picture - Jonathan will provide those in due course. However, the point is that Chicago was SLIGHTLY warm, but most marathons here in SA would give anything for such good race conditions. Same for Kenya, where the conditions in Chicago might be described as perfect for running. There is something wrong with the perceptions of running and the heat in the USA, the "experts" really have no idea about it.

Drink early, drink often, was a mantra repeated many times by the commentators, as though that helps more than just drinking to thirst...you'd have thought these guys were running in the Sahara desert with humidities of the Amazon jungle. Beijing was worse, and Sammy Wanjiru should have made us all sit up and rethink our understanding of how the heat impacts racing strategy after his 2:06:32 win, but alas, more of the same from the "experts"! It didn't affect the elites too badly, however, though the times were perhaps a minute or slower than might have been expected with perfect race conditions.

However, for more detail, there's no one better in the world than Jonathan to comment, since he was right there, in the medical tent, doing a research study specifically to examine the changes in conditions on the course. So our post-race analysis will focus more on that - join us for posts and insights from the tent later in this week!


Friday, October 10, 2008

Chicago Marathon Preview

The 2008 Chicago Maration: Race Preview

Well, the second big marathon post-Beijing happens in Chicago on Sunday, and it promises to be a great race. Very different from the Berlin Marathon, where Haile Gebrselassie made a concerted effort (and ultimately a successful one) at his world record.

No talk of a world record in Chicago, but a far more competitive race is without doubt on the cards. For the best preview of the names to watch, check out the analysis done by Letsrun.com. They looked at the top 5 men and women over the course of the last week, and you can read their final prediction article here for the men and here for the women. If you're watching the race, it's well worth the read.

From our side, the race has personal significance, because as you'll recall from Jonathan's post last weekend that he'll be involved in the medical tent doing research on the race.

That research, in turn, was driven by the events of last year's Chicago Marathon, which was one of the most dramatic, controversial and spoken about races in many years. From a racing point of view, it produced two of the most dramatic finishes you will ever see in a marathon in BOTH events. On the men's side, Patrick Ivuti and Jaouid Gharib raced shoulder to shoulder through the finish line, almost cleaned out the men holding the tape, and eventually Ivuti was declared the winner.

On the women's side, Andriana Pirtea of Romania, running her first ever marathon, came into the final 400m with a large lead over Birhane Adere, and had even begun waving to the crowd and celebrating her win. Adere didn't read the script, however, and she pressed one last time, caught the Romanian (whose reaction when she realised that the Ethiopian closed her down was one of the highlights of the marathon year) and won her second title.

But the real drama, for most people, was still to come. The race was cancelled earlier due to the excessively high temperatures, and the number of runners who were collapsing, bailing and struggling in unseasonally hot conditions. More tragically, we had a death, that of Chad Schieber, a 35-year old policeman from Michigan, who collapsed at the 18 mile mark of the Chicago Marathon, and was later pronounced dead. This tragic event, together with approximately 300 other medical cases, prompted the race organizers to take the unprecedented step of shutting the course down after about 4 hours of running.

The reaction to the decision was varied, emotional and ultimately, we believe, inappropriately harsh. Race organizers were heavily criticised for failing to provide water, for not cancelling the race sooner and a variety of other decisions deemed to be harmful. We tried to cover that story and the fallout in as much detail as possible, explaining that dehydration, which was blamed for the death, was in fact NOT the issue - you can read the posts on Chad Schieber here and here.

This year's race is not expecting a repeat of the same - it is supposedly going to be a decent day for racing. Not perfect (like Berlin), but definitely more manageable than last year, temperature-wise.

However, Jonathan will be able to bring you all that information, straight from the front lines in the course of the next week.

Before that, we will bring you the race analysis, including our usual fare of pacing, split times and race commentary. So join us on Sunday evening/monday morning for our race analysis, and then in the week after the race in order to unpack Chicago 2008.


Tuesday, October 07, 2008

1:59:59: The Sub-2 hour Marathon?

1:59:59...will we ever see a sub-2 hour marathon?

It's been just over a week now since Haile Gebrselassie ran himself into history (again) when he broke his own world record by running 2:03:59 in Berlin. More important, he also broke the 2:04 barrier, which gave even more impetus to the usual speculation that accompanies a world record. At the time, I wrote that we'd look at the future of the marathon once the dust had settled. I guess it's well and truly settled now, apologies for the delay, but here's our take on the question that has been a topic of some discussion in the last week or so - will man ever run a sub-2 hour marathon?

Barrier-breaking speculation

It's quite normal for (sometimes wild) speculation to accompany any world record - it happened last year as well, with Gebrselassie predicting a 2:02 in the near future. He tempered that enthusiasm this time around, saying that he felt like a 2:03:30 was possible. Dave Bedford, the race director of the London Marathon, was not quite so circumspect, and his words last weekend were: "Without doubt I will see a two-hour marathon in my lifetime. It might be towards the end of my life. It might be another 20 years. But, yes, it will definitely happen."

Dave Bedford, for the record, is 58 years old, and perhaps the best response to this I've seen is from the guys over at LetsRun, who wrote that he'll be wrong unless he plans to live to 138 years old!

That's the sentiment of most - they are saying that it's a long, long way off. For example, Glenn Latimer, who oversees distance running in the USA was quoted as saying that the sub-2 hour marathon is a "far-off dream", and that "If you look at what his splits were, averaging around 14 minutes 45 seconds for each five kilometres, they're amazing. You're talking something else altogether to go down significantly below this". So he reckons it's a little soon to be excited by a sub-2 hour performance just yet.

I thought I'd take a little more of an analytical look at the chances, borrowing a little from the history the event, and also the commercial aspects that might, in some respects, prevent many great athletes from breaking the record, thus slowing improvement. Then I'll scan "the lay of the land" to see just who might come through in our lifetimes (assuming that Dave Bedford does in fact reach about 90 years old) and do what Bannister did for the 4-minute mile. One must of course be mindful that people, including scientists, have often painted themselves into a corner with this kind of rationalization in speculation. But here's our take on the sub-2 hour dream!

Understanding where the current "golden era" comes from - looking back

The starting point in trying to predict the future is understanding the past. And there is no doubt that marathon running is in something of a golden era. Remember, in 1998, the world record stood at 2:06:50, by Belayneh Dinsamo of Ethiopia. That's only ten years ago, but the record was already 10 years old.

However, we then had a flurry of world records, first Ronaldo da Costa and then Khalid Khannouchi taking the record below 2:06, to 2:05:38, through their collective efforts in the late part of the 1990's.

All the while, the world was waiting in eager anticipation for the next generation to turn to the marathon, because great things were expected from them. That is, Paul Tergat, Haile Gebrselassie and Salah Hissou had been rewriting the record books on the track, over 10,000m, and when they eventually moved up to the marathon, the general perception among the running community was that we would be in for some major overhauls!

And so it proved. Hissou disappeared (anyone know what happened to him?), but Tergat and then Gebrselassie certainly delivered on the expectation, even if it did take them a few attempts before they got it right. Therefore, what we are seeing in the marathon today is very much a function of what we saw on the track over 5,000m and 10,000m in the 1990's.

Take a look, for example, at the following table. It shows the world record over 10,000m.

The 10,000m world record was lowered by an incredible 30 seconds over a four-year period thanks to the efforts of Gebrselassie, Tergat and Hissou. Who can forget their duels in two Olympic Games, and in particular, it was Tergat who drove one of the most spectacular periods ever seen on the track in his battles with Gebrselassie.

The point is that this kind of performance over 10,000m predicted what would eventually happen in the marathon, because we know that the best predictor of 10km time is peak treadmill running speed (measured in a lab-based test), and the best predictor of marathon performance is 10km performance (much better than VO2max or lactate thresholds or heart rate measures, for example).

A similar thing was happening in the 5,000m event - Gebrselassie first broke the record in 1994, and over the next four years (up to 1998), it fell by an astonishing 18 seconds! It then took another 6 years to fall by 2 seconds, quite clearly showing that unless a new generation of incredible runners arrives, we're heading into a very flat part of the progression curve...

So given the explosion in 10,000m and 5,000m times of the mid-90's, the sudden drop of the marathon world record was on the cards.

Looking ahead - is it sustainable?

So what, you ask, is the point of all this? Well, there are some important points arising out of this observation.

First of all, the 10,000m record has stablised somewhat since 1998, and the peak of the Gebrselassie-Tergat era. Yes, Kenenisa Bekele has entered the fray and lowered it by a further 5 seconds, and so we are rightly excited at what he'll do when he turns to the marathon. However, other than him, the depth and quality of performances over 10,000m have not continued to improve. After knocking 30 seconds off the time in four years, we've only seen 5 seconds in the next 10. The 5,000m record, meanwhile, has dropped only 2 seconds in six years, and only thanks to one individual.

Therefore, applying the same process as above, the marathon record cannot be expected to continue falling at the same rate, with the possible exception of Bekele, and maybe one or two new runners, as yet undiscovered, in the next few years.

Secondly, and more important than this, you have to ask yourself the following question: If a 26:30 10,000m runner steps up to the marathon and is able to run 2:05:00, then what kind of shorter distance speed would it take for a runner to do a sub 2-hour marathon?

Hopefully, you'll recognize that breaking a 2-hour marathon does not simply happen in isolation - it is "linked" to other distances, in as much as performance over those shorter distances predicts what happens in a marathon. You cannot, for example, hope to run a 2:05 marathon unless you have a 10,000m capacity quite well below 27 minutes. It's impossible to extrapolate with precision, of course, but if you want to run a 2-hour marathon, then you have to be running something faster than 25:30 for 10,000m in my opinion!

So the next time you ask whether a sub-2 hour marathon is possible, think of the implications - a 25:30 10,000m time? And considering that in ten years, arguably the greatest distance runner ever on the track and country (Bekele) has dropped it by 5 seconds in ten years, then how long will we wait for a runner with that kind of speed?

More obvious, perhaps is the implication of a 2-hour marathon on half marathon times. Currently, the half marathon best stands at 58:33, by Sammy Wanjiru. In order to see a sub-2 hour marathon, that would need to drop to 56 minutes, at least. How likely is that? 20 years? I doubt it...

The next generation: Who can advnce the marathon? The pool is shallow...

So rather than get carried away with the explosion of marathon records in the last few years, one has to look at the pattern of transition from the track to the road and then ask whether it can be expected to continue. I feel that the answer is "No", because other than Kenenisa Bekele, there are currently few 10,000m runners who possess the speed and ability to move the event forward like Tergat and Gebrselassie have. Sileshi Sihine, eternal silver medallist behind Bekele, is a runner who should also be capable of a 2:05 time, but not the kind of progress that is required to go under 2:03, let alone 2 hours.

Another runner who may prove very successful in the marathon is Zersenay Tadese. 10,000m is probably too short for him, and he seems to be a runner more suited to the longer distances. He's already succeeded on the roads, breaking 59 minutes in the half marathon, and winning the Great North run in a course record in 2005. That kind of pattern suggests that he is capable of a brilliant marathon, and I dare say he's the one man of the current track generation who will challenge Bekele when they all run the marathon. I would hazard a guess that Tadese is capable of a 2:04, maybe even slightly quicker, while Bekele is a 2:03:30, or thereabouts. Quite who is going to run 3 minutes faster than this is anyone's guess, and that's why I feel this talk of a 2-hour marathon is very premature!

The current number 1: Sammy Wanjiru. How commercial barriers may prove crucial in preventing record progress

Then of course, there is Sammy Wanjiru. At just 22, he is omitted from the earlier discussion of track runners, because he made the jump to the marathon without following the 'classic' path of focusing on track first. That's not to say he's not a great track runner - has a 10,000m PB of 26:41, run as a junior, and so I dare say he falls into the same caliber of speed-runner as Geb, Tergat and Bekele one day.

In my opinion, Wanjiru is the best marathon runner in the world today. In fact, I'd put his 2:06:32 Olympic win ahead of Gebrselassie's World Record on a list of all-time performances, firmly at number 1.

And if Wanjiru is able to run the right race, on the right day, with the right pacemakers, I think he's capable of the world record right now. For that matter, so is Martin Lel, also of Kenya. Remember, Lel outkicked Wanjiru to win London in 2:05:16, at the end of what became a tactical race over the last 7km, and he finished with a 60-second 400m sprint! So don't count Lel out just yet.

But Wanjiru seems to hold the aces, and I do think he's probably capable of a 2:03:40-ish time.

Having said that, the big dilemma for all marathon-record hopefuls is "Where do they run it?". The record is now so strong and difficult to break that it requires the very best conditions - perfect course, perfect pacemakers, and of course, perfect money. That happened in Berlin, and Gebrselassie seems to have found his other "perfect" course in Dubai, where he'll get a cool million dollars if he breaks the record again (he's running in Dubai on January 16).

But the requirement for money, pacemakers and perfect weather and course make it very difficult to break the record. Can you see Gebrselassie allowing his yearly "time-trial" in Berlin to become a race for the record with Wanjiru? I certainly can't. For three years, Geb has been Berlin, it's basically a huge marketing campaign for sponsors with Gebrselassie's time-trial the focal point of the race. Introducing challengers, particular with other sponsors, hardly seems smart. The cost would be prohibitive anyway.

And so rather than facing a physiological barrier, I think that one of the main barriers facing marathon running now is commercial - are there races out there with sufficient prize money to draw the top names, to pay the best pacemakers? And then of course, it can't be any race - it must be pancake-flat with no wind and perfect weather. That's a very difficult ask, and it means that maybe only a handful of races exist. If Wanjiru wants to win London (or any of the other big races, like World Champs), then he cuts his chances by half. So where then, will the record come? Forget physiology, the biggest barrier is logistics!

All things considered - don't hold your breath for a 2-hour time any time soon. I think it will be surprising if we see a 2:03:30 clocking in the next ten years, and maybe then it will be Bekele or Tadese. But it will take maybe five or six generations before we even get to 2:02, let alone 2 hours. But then this site will hopefully still be around (we'll find someone to take it over when we move on, our great great great grandchildren maybe!), and so if it happens, we'll eat our words!