Ask an Expert: What’s the Secret to Training for Races in High Heat?

Jeff Knight
by Jeff Knight
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Ask an Expert: What’s the Secret to Training for Races in High Heat?

Here at Under Armour, our team is full of experts — across multiple sports — who want to make you the best athlete you can be. To that end, we’re pumped to introduce a new series called “Ask an Expert.”

The idea is simple: Every so often we’ll ask the MapMyRun community (That means you!) to submit a running-related question on MapMyRun’s Facebook page or Twitter handle for an Under Armour expert to answer. If you’re anything like us, running leaves you inspired but sometimes confused. With our in-house running experts, coaches and pro athletes at the ready, we’ll do our best to clearly answer your most burning questions.

Have a running question that you want answered by our experts? Simply post on the MapMyRun Facebook page or the @MapMyRun Twitter handle with the hashtag #AskAnExpert.

In this premiere installment, we tapped Jeff Knight, our resident Clinical Exercise Physiologist, who knows his stuff when it comes to running and human performance. Outside the lab, Jeff coaches beginner to elite runners at Rogue Running in Austin. He’s the man when it comes to this question:

I’m racing the Cumberland Plateau Stage Race in Tennessee on Aug. 26. I live in Utah, at an altitude of 7,000 feet with summertime highs around 75 degrees, so the race-day conditions couldn’t be more different than what I’m accustomed to. How should I prepare to race in weather with 90-plus degree temperatures and high humidity?
— Steven Murphy, Park City, Utah

Jeff Knight: That’s a great question! But really we have two questions. Since you live at altitude, you may also ask: “Do I need to do anything at all?”

For ages, running coaches have sworn by training at altitude for hot, humid races and vice versa. Likely fueled by that, there have been a number of recent studies exploring the carryover gains you experience from training in a hot, humid environment for a race set at altitude, and the studies suggest it works! Now, you’re talking about the opposite scenario — training at altitude and racing in humidity.

While there aren’t clear studies on this that I am aware of, the physiological response to training at altitude in theory would help you for a hot, humid race. Expanded blood volume, for example, would help with sweating and keeping your core temperature down, but I wouldn’t rely on that. So back to your original question: How should you prepare for a race in heat and humidity?

The answer is: like everyone else.

Whether you live at 7,000 feet or 500 feet, racing in the heat calls for acclimation training. Fortunately, with two weeks to go, you have just enough time to get some acclimation training under your belt. The biggest boost in heat acclimation occurs in the first week of heat training. The following 1–2 weeks continue to yield improvements, just at a lower rate. With regards to how much to do, a 2015 consensus statement from top heat-exercise researchers recommended you spend about 60 minutes a day training in the heat. Thus, the last 14 days of training should incorporate about an hour of heat training per day if possible.

To do some heat acclimation, first consider if you have the opportunity to train in hot and humid conditions. For example, do you live somewhere that gets really hot in the afternoon? If you normally train in the morning, switch up your training, and do your runs in the afternoon. Similarly, if you own a treadmill, crank up the heat, or turn on some space heaters to make your treadmill environment as close to race-day conditions as possible.

But what if you don’t have this option? There’s been some research around training while wearing many layers to simulate hot conditions if you live in a cooler climate, but results are mixed, likely because sweating is different since the clothes get drenched in sweat and your skin becomes saturated with moisture. That said, if it’s the only option you have, go for it. It’s likely better than nothing.

The final option comes from a 2015 study that showed athletes who followed their normal training schedule but supplemented it with 30 minutes in a sauna for 10 days experienced better performance in the heat. That is, if you simply can’t find a way to train in the heat during these last couple of weeks of training, go spend 30 minutes in a sauna at your local gym. Just be sure to hydrate afterward!

Now for a few words of caution: Training in the heat means more sweating and higher carbohydrate burn. Make sure you are staying on top of your hydration and carb intake, especially if you’re carbo-loading. Also, your heart rate is higher by 10 beats per minute or more when training in the heat, and you may be slower, so don’t freak. With two weeks to go, you’ve done all the training you likely need, so if you run a little slower, it’s going to be OK.

In the end, even though you live at altitude, I recommend you do something. Almost unequivocally, runners who prepare for a hot, humid race by training in hot, humid conditions perform better on race day than those who don’t. So if you want an edge, get out into the heat.

About the Author

Jeff Knight
Jeff Knight

Jeff Knight is a clinical exercise physiologist for Under Armour. He coaches runners at every level, from the grade-school  to professional athletes, including many U.S. Olympic Trials qualifiers. Jeff has overseen run training for one of the largest adult running groups in the U.S., providing training plans for more than 3,500 runners per year. Jeff holds master’s degrees in exercise physiology and biochemistry and has a passion for all things sports science, particularly improving basic health through smarter exercise and technology.  


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