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Thursday, October 25, 2007

Chicago Marathon death - no evidence of dehydration

In the last few weeks, we have run a series of posts investigating the events of the 30th Chicago Marathon, where record high temperatures caused the early cancellation of the race, amid record numbers of medical cases and emergencies. We discussed the possible cause of these collapses, suggesting that blood pressure and unfamiliarity with the heat were more likely the cause of the problems than dehydration and heat stroke, which were being blamed for all the problems.

We also did a post looking at the sad death of Chad Schieber, a 35-year old policeman who collapsed at the 18 mile mark and was later pronounced dead. Initially, the death was blamed on the heat and dehydration, but the initial autopsy found that Schieber suffered from a relatively common condition known as mitral valve prolapse. This condition, which is reported to affect 2% o the US population, does not by itself cause death in athletes, but has been implicated as a contributing factor to a potentially fatal arrhythmia.

New reports from the Medical Examiner

Now, just over two weeks later, the medical examiner's office has released further reports that "tests show no evidence of dehydration." According to Nancy Jones, the Cook County Chief Medical Examiner, dehydration can now be ruled out.

In response to our initial post on this death, where we suggested that it would be prudent and wise to hold the verdict until the autopsy result was announced, a few medical doctors wrote in saying that dehydration may contribute to the death. A few things in response - firstly, there's no evidence for that, it's pure supposition, because until one has actually studied the physiological response of people with mitral valve prolapse to graded dehydration DURING exercise (very important - it must be measured during exercise, as we've tried to emphasize in other posts recently), it's supposition to say that "dehydration contributed to the death".

But in this latest news, what are referred to as "dehydration tests" (presumably measures of body water) have confirmed this. Again, there's an issue around what constitutes "dehydration" - is it 1% body weight loss, is it a change in total body water of "X" %? That's unclear. But it does seem more and more that it was not a dehydration issue.

The new blame-game - not dehydration but lack of maps

Instead, it seems that attention is now being turned to the ambulance and the length of time it took to get Schieber from the course to the nearest hospital. According to one news report,

"You can actually see the University of Illinois at Chicago Hospital from where Schieber collapsed. It takes a minute and a half to get there. But the ambulance took between 8 1/2 and 14 minutes."
Unfortunately, this type of thing does tend to happen after such tragic events. But hindsight is always 20/20, and it's a shame that blame gets assigned so easily. Not that one should gloss over potentially critical details, lest we forget to learn from (possible) mistakes

But this does make me think back to the Comrades Marathon this year, where a runner collapsed perhaps 300m from the finish line. His fellow runners, seeing him lying there without medical support, picked him up and carried him across the line. Sadly, he was pronounced dead at the scene. But then even worse for all those involved, the runners who had attempted to help him were accused of contributing to his death! There was some physiological basis for this (you can read this in a post we did on it here), but it was a shame to have to play that game at such a time, in such a public forum. The death of Chad Schieber seems the same.

Our future posts

To wrap up on a related theme, we're very much into the thick of our series on Fluid Intake and Dehydration: Exploding the myths. We've recently looked at the comparison between laboratory and field studies, having previously explained how it was the advent of "science" into marketing that drove a good deal of research in lab studies. In Post IV of that series, we'll look at the physiology of thirst and what the body is actually defending, as we ask the question: "Is thirst enough and how does it work?"

So do join us for the completion of that series.

In other news, the New York City Marathon takes place on the first weekend in November, and many runners are no doubt hoping for much cooler temperatures. Regardless of what happens, you'll be able to read all the race insights and stories right here!

Join us then!
Ross and Jonathan