Heat Training | March 13, 2011
The Firetrails 50 is a moderately difficult fifty mile trail race held every year in the East Bay area near San Francisco in mid October. It attracts a large (over 200) and mostly experienced field of ultrarunners. I ran the race in 1995, 1996, 1999, and 2005, and each time I showed up well trained and uninjured. I had the following results: 9:46, 9:55, 11:30, and 9:44. So what, you may wonder, happened in 1999 that I was almost two hours slower than normal? The answer is: Heat happened.
Instead of the usual moderate fall weather, we had temps that soared twenty degrees past normal into the mid nineties. It devastated the field. Runners were dropping like flies at the aid stations and almost everyone who toughed it out on the exposed trails was in a death march shuffle. Despite being extremely slow compared to my other finishing times, I placed in my usual slot about one quarter of the way down the field in 45th place. The heat had been an equal opportunity employer, slamming everybody, not just me.
Heat will have a definite impact on your running. The same moderate, comfortable pace on a cool day can register as a hard and punishing effort on a hot day. Dehydration becomes a bigger risk in elevated temperatures, and if you push too hard in the heat, you risk heat exhaustion or heatstroke. The good news is that you can become acclimated to the heat with proper training, and though you can’t eliminate the risks that heat brings on, you can significantly reduce the risks and make the effort seem a lot less unpleasant.
Everyone will have a different starting point in their heat training. My running buddy, David Nakashima, has an incredibly efficient cooling system. We’ll train together on a slightly warm day and he’ll soak through his shirt long before I even break a sweat. Conversely, David is fully dressed with tights, wool cap, gloves, and a jacket in cool weather when I’m still more than comfortable in a t-shirt and shorts. He can perform well in races with temperatures in the nineties and above. Once the temperature gets a little over eighty in a race, I invariably feel the effects both in my perceived suffering and in my slower times. You’ll need to find out for yourself where your comfort zone ends.
If you are planning on a race with the potential for high temperatures, you should spend some time heat training in the months leading up to your race. The mechanics are pretty simple. Instead of running during the comfortable morning or evening hours of the day, pick the hottest part of the day and do your workout then. Each week make one of your runs, a heat training run, and make sure that some of your long runs include the hotter hours of the day. If your area doesn’t offer the right conditions, compensate by overdressing for some of your runs. The more heat training you do, the more your body will acclimate and allow you to go farther and faster in hot conditions with less perceived discomfort.
When you heat train, wear light-colored, lightweight clothing that covers as much of your skin as possible. Don’t skimp on the sunblock and be sure to take lots of water with you or plan on frequent water stops along the way. Experiment with different types of salt replacement supplements and electrolyte drinks. You’re searching for a balance: how much to drink without drinking too much and how much salt you need to replace without overdoing it. The most important thing you need to do is to take it slow. In the heat, if you maintain too high a level of effort, your body’s ability to dissipate the heat fast enough will fall behind and your core body temperature will start to rise. You can usually tell when this begins to happen. Your discomfort level goes up. You feel your temperature rising. One runner said it feels like your head is the top of a thermometer that is about to explode. When this happens, stop running and walk until you feel comfortable again.
When you actually do race in the heat, you are going to need to make some adjustments. First of all, lower your expectations about your finishing time. The heat will probably slow you down considerably, although you might still place as well as ever in relation to the other runners in the field. In fact, if you’re well prepared, you might finish ahead of some runners who normally race faster than you. Bring an extra bottle so you’ll have plenty of water capacity between aid stations, or consider using a hydration pack even though you usually race with bottles. Go out at a moderate pace and watch for signs that your core body temperature is rising. Walk if you start to feel overly hot. Take every opportunity along the way to cool off. Get ice in your fluids at the aid stations and leave with some ice underneath your hat. Scoop water over your head from any streams you might pass or at least soak your hat in the water. In fact, on a really hot day, it’s worth your time to get right down in the water in a river or stream and cool off completely. Just be sure to pick a safe spot. Heat can cause your stomach to feel upset making it unappealing to eat and drink. But you especially need to keep drinking, and you should try to keep up with your usual eating routine. Use your electrolyte replacement tablets or drink to replenish your salts. Sometimes bringing your electrolytes back in balance will ease your stomach problems.
Heat training is a challenging part of ultrarunning but ultimately it is well worth it. There are many races that almost invariably require you to run in very hot conditions. A perfect example is Western States, where the question is not if there will be heat in the canyons between Robinson Flat and Foresthill but just how hot it will be. One year there, I was making the infamous climb up the switchbacks toward Devil’s Thumb and the heat was fierce. I passed three runners who were stopped in their tracks, one of them getting sick as I went by. Farther up I passed a couple of other runners who were still moving but visibly flagging. No one was more surprised then me that I was doing so well since I never thought of myself as good in the heat, but I had been doing quite a bit of heat training that year, and lo and behold, it was clearly paying off.