Boston Marathon Recap: Handling the Heat

Marathon champion Wesley Korir on Heartbreak Hill. (Photo by Rob Larsen via Flickr.)

Physiologist and running guru Jack Daniels once wrote in his seminal runner’s handbook, Daniels’ Running Formula, that “the exercising human body is far better designed to handle cold than it is to deal with heat. For a runner, particularly a distance runner, heat is enemy number one.”

Nowhere was this more evident than at Monday’s Boston Marathon, when temperatures skyrocketed up to the high 80s. The event kicked off early with a cautious women’s elite group running at training pace — afraid to tempt Hephaestus. The men followed only slightly less gingerly. Despite the caution of professionals and mortals alike, crestfallen runners quickly lined the side of the course. The defending champion and the most dominant runner of 2011, Geoffrey Mutai, stepped aside for medical assistance upon reaching the hills, while the women’s 2011 champion, Caroline Kilel, met a similar fate as she failed to make the finish line. The ultimate winners, Wesley Korir and Sharon Cherop, were able to claim the champions’ laurel wreaths, but they did so with two of the slowest times in years.

Running in heat is hard. According to a study published by the B.A.A.‘s Matt Ely and his colleagues at the U.S. Army Research Laboratory in Natick, marathoners slow by more than four percent at temperatures similar to those experienced on Monday. It doesn’t matter how well-trained the athlete might be: as the body heats up, blood is diverted to the skin, leaving less of it available for transporting oxygen to the muscles.

Sweating only adds to these issues. True, it’s our body’s natural adaptation for keeping cool in hot weather, but it makes staying hydrated even more essential. Significant drops in performance occur when you lose more than two percent of your body weight through sweat — and remember, it’s not only water that needs to be replenished, but also salts and sugars. Runners can do this with sports drinks, gels, or candies — some resort to drinking pickle juice for the salt, but this is probably excessive. Heavy sweating can also further reduce circulating blood volume, which puts an excess stress on the heart leading to higher perceived effort. It’s also critical for anyone planning to run a warm marathon to practice drinking while running in practice. As we saw, even many of the top athletes at the Boston Marathon struggled with cramping as they tried to drink more water on the go than they were accustomed to.

That said, although the heat humbled even the best athletes, more than 20,000 runners were still able to complete the 26.2 miles in these grueling conditions. I asked some local runners how they coped with conditions on Monday.

“I actually enjoyed not worrying about my pace and just moving along,” said Stephanie Burnham, from Manchester, NH. “I didn’t pay attention to my pace at all … I think that helped a lot.”

Maine’s Sheri Piers was the top American female finisher (tenth place). She told me that she adjusted her goals when she heard the weather report. “I ditched my watch and focused on place. In terms of the heat, I do best in that kind of weather because I don’t sweat very much … I don’t know why, but I was not bothered by it today. I hit every water stop and kept myself wet the entire distance. The fans were exceptionally helpful and dragged me through the entire finish.”

My friend Louis Raffetto, who runs for the B.A.A., took more extreme measures in an attempt to keep his body temperature down before the start of the race. “I froze a t-shirt and let it thaw enough this morning so that when I put it on before heading to the start, it was still a bit frozen and nice and cool. It kept me cool on the walk over and while waiting around in the corral.”