It’s hot. It might be raining in the Village Départ this morning but the forecast is for dry, hot weather. Yesterday Sylvester Szmyd said his SRM recorded the temperature at 39°C during the stage. And there’s no end in sight, the forecast says another week of temperatures well above 30 degrees (above 100°F for US readers).
The initial consequences are predictable. Riders drink more water, sweat rolls into the eyes… and wounds. Spare a thought for the domestiques who have to ferry bottles more often, dropping off the bunch and coming back is not easy. Repeating this ten times in a stage is a hefty threshold workout right during the middle of the race. You also lose precious minerals, hopefully riders will be topping up with electrolytes but often riders just want to drink water.
You might think there are two ways to lose water, sweating and peeing. But there’s a third: breathing. Just as your breath on a cold day sees the moisture condensing, on a hot day the moisture is also coming out, only more. A bit like a dog using its tongue as a cooling device, your lungs exploit the exhalation of water for cooling via evaporation. When you are riding hard, lungfuls of sauna-hot air going in and out can result in significant water loss over time alone.
As for the wounded, and there are plenty, the hot weather can makes things harder. Garmin-Transition’s Toby Watson was kind enough to reply to a question I put to him about the heat, asking if it was good or bad for the wounds. He says “Heat’s worse. Sweat in wounds, bodies more stressed (so slower healing) and there’s more blood to skin, so more swelling.“
There’s also melting tarmac and hot sun. Yesterday ex-pro and L’Equipe pundit Jean-François “Jeff” Bernard said the breakaway trio were going to get a suntan but little else, knowing their chances were doomed. Jokes aside, the sun will make more riders tanned and some will burn. Red skin means precious blood flows to the skin, not the muscles.
All that’s the usual fare. But there are additional factors. You sweat more and I’ll spare you the detail but it means more saddle sores, especially if a rider has to sit around in their shorts for too long after a stage. Heat can also be an appetite suppressant, a threat during the race of course.
Then there’s getting a good night’s sleep, often this can be hard if you’re sweating in a hot hotel room. What about air con? Well I remember FDJ’s Marc Madiot saying he bans air con in hotel rooms, fearing riders get cold in the night. The sadist! But there’s long been an old-school thought that riders with very low body fat always need to keep on the warmer side and avoid a chill.
Finally some riders cope better than others, genetic and physical factors come in to play. How much do they sweat, the body’s surface area and more. In general a tall lanky rider presents a larger surface area relative to muscle mass and internal organs and this allows for better cooling: think Robert Gesink. But it also depends on sweat rates.