Keeping cool at the Olympics
Despite the lack of cheering crowds in the stadia, the Olympic games are still making for some absolutely riveting TV. But alongside the sport, there's also a lot of physiology being showcased if you know where to look, particularly since the athletes are battling some very high temperatures, which some are clearly better prepared for than others. Chris Smith spoke with Cambridge University's Christof Schwiening, who runs marathons himself and is also an expert on how the body controls its temperature and the best ways to maintain performance when the mercury begins to climb...
Christof - I've been watching a lot of the women's events recently. The women's triathlon and the women's road race were really nice examples of seeing athletes who were one, very well-trained and they were, on the whole, the ones at the front who were doing the kind of things that I would advise them to do, then those just behind them who were doing the right things on race day to compensate, but not having quite got their physiology in the best possible place. So the triathlon, if I can give you a quick example of the women's with Flora Duffy who came first. And she was on the final run, really just focusing on running, and she wasn't doing much in the way of drinking water or eating anything. She was just running. So she was excellently trained. And Georgia Taylor Brown, who was just behind her, not as well heat adapted so she probably hadn't had quite the right training, and she was dumping water over herself. And if you watch the video, it's absolutely fantastic. She's taking two bottles, dumping the water over herself at virtually every stop that she can. And I think that's a fantastic strategy. So as a physiologist is wonderful to see both the training and the race execution coming from the two different parts of the sort of training spectrum.
Chris - So is this all about heat then?
Christof - Well it's not just controlling body temperature, it's also pacing and adopting the right strategies. So I have a nice example in that I did a race actually, about 10 days ago, at 30 degrees C. It was a half marathon race at Eton Dorney. And I'm not terribly well trained at the moment, I'd say I'm actually quite unfit, but I set off in the race with exactly the same strategy as Georgia Taylor Brown, dumping the water over myself. And I started off very carefully in terms of the pacing, so considerably slower than the time that I could have got in cool conditions. And I think that's the critical thing because as you develop in the race, as it goes on and you get past the sort of about hour mark or so you see people really overheating and they're slowing down, having to slow down to cut their metabolic heat production to avoid their core body temperature going too high. And of course, there were runners collapsing all over the course. And I found myself, as these runners were going down, shouting out "Pour water over him!" as they were saying "His core temperature is up at 40 degrees C!"
Chris - Is the best approach just to drink a whole heap more water then?
Christof - No, why on earth drink? Because if you drink, you've got the middleman of your gut. So you put the water into the gut, and then you've got to get the blood flow to the gut and you don't want the blood flowing to the gut. You want the blood flowing to the muscles, into your lungs. You don't want it going to the gut, but you've got to have blood flow to the gut to grab that water and then get it into the actual bloodstream. And of course, if you haven't heat adapted, all that happens is that water that you get into the blood goes into the cells of your body instead of the bloodstream because they've dehydrated as a result of the sweating. So I think external cooling is absolutely the key thing to do in the heat, cut out the middleman and dump the water on you, cutting out the whole process of sweat production.