A Beginner’s Guide to Running in the Heat

If you live in the Northern Hemisphere, there are good odds that you’re currently dealing with tremendous heat on a daily basis. This can make training for triathlon tough — especially when it comes to the run. (You can certainly overheat while training on the bike or in the pool, but the run is the most demanding when performing in the heat.) To help ensure that you can still complete your training as planned — heatwave or not — Slowtwitch got some tips from Jason Lentzke, a Phoenix-based triathlon coach who has helped countless athletes deal with, and beat, the heat en route to big results on race day.

Stay Hydrated

Lentzke has been coaching in Phoenix for over a decade, and he says that in that time he has learned that you can certainly deal with the heat, but it’s “just a matter of tempering expectations.”

An obvious key to success for running in the heat is to drink plenty of fluids, but Lentzke says a lot of people fall short on that front and show up to training sessions (or even races) dehydrated or under-hydrated.

“It’s a big oversight for many athletes,” he says. “They think about inter-session fuelling, but not the 24 or even 48 hours before.”

Lentzke says hydration is something athletes should be thinking about at minimum one day before a big session, especially when it’s hot outside. This means sipping water throughout the day and limiting caffeine and alcohol consumption if possible.

Once you get to the workout, Lentzke says it’s necessary in extreme heat to have water with you (or nearby) at all times. You can, of course, carry a bottle, whether that’s in your hand or on a hydration belt, but he says he personally can’t stand carting water around on runs. Instead, he strategically places bottles along his route.

“It takes a bit of extra planning, but I’ll plant bottles the night before,” he says. “That way I know I have places where I can stop for a drink.”

Another option is to run loops so you can stop at your house, car or wherever you started your run every couple of miles for a mandatory water break.

“Mentally, it’s a bit of a drag to run loops, but it makes it so much more enjoyable when you have your own kind of mock-aid station,” he says.

Forgetting Pace

Lentzke says it’s OK to sometimes run in the heat, but you have to approach it differently than you would on a cooler day.

“You need to remove the metric of pace and just focus on effort and heart rate,” he says. “I encourage athletes to do that rather than trying keep the same pace they would run in 50 degrees.”

Lentzke says that even some hard workouts can be run in the heat, but you have to be smart about them.

“It depends on the workout,” he says. “If you’re ripping 400s at zone 5, that is just going to surge your core temp. Once you surge your core temp in hot conditions, you’ve kind of just blown the fuse.”

For workouts with longer repeats, however, he says you can make it work.

“Instead of five by one mile at 6:30 pace, do five times one at at 6:30 effort,” he says. “You know what that feels like, so don’t sweat it if it’s 30 seconds or a minute per mile slower. It doesn’t matter.”

He continues, saying, “when you’re training in the extreme heat, you’ve just got to have that mindset that pace is kind of irrelevant.”

Benefits of Heat Training

Lentzke notes that there are benefits to training in the heat, but you have to be smart about it. For one, you will “become heat-adapted” if you run in hotter temperatures enough.

“Your body will slowly get better at cooling itself and running more efficiently the more you train in the heat,” he says. “You just have to stay patient.”

That patience is quite important, Lentzke says, adding that “one hot run won’t make you heat-adapted.”

He says that “most meaningful adaptations” take “two or three weeks of exposure.”

That means two to three weeks of running carefully and consistently in the heat without overdoing it. Then, even when you are feeling more comfortable in the heat, you still have to put a big emphasis on doing it safely. Just because your body is getting better at dealing with those conditions doesn’t mean you can go back to hammering workouts and focusing on pace. Lentzke says heart rate and effort are the name of the game no matter how long or how well you’ve been running in the heat.

Lentzke adds that heat training is sometimes referred to as “the poor man’s altitude,” noting that it can give you great physical boosts if done properly.

“One of the first adaptations to heat is the expansion in blood plasma volume, so basically the liquid portion of your blood,” he says. “This allows your body to pump more blood, maintain blood pressure more effectively and send more blood to your working muscles.”

Lentzke says you will “never full adapt” to the heat (“Phoenix in July still feels like Phoenix in July, even 10 years into your time here,” he says), but you will become more “heat-tolerant” the more you train in hotter temperatures, giving you an edge on race day.

“Then, once you get the first cooler day with a bit of crispness in the air in the fall, it’s like coming down to sea level from altitude,” he says. “You feel like a rockstar.”

Avoiding the Heat

While Lentzke is a proponent of training in the sun and the heat, he says that there is of course a limit. Every individual athlete will have their own line that they have to determine on their own, but whatever your limit is, it’s important to stick to it and adjust your training accordingly if the thermometer hits that number.

“You’ve got to get out early sometimes,” Lentzke says. “Most of my athletes are based in the southwest, so when I see an athlete logging a run at 6 a.m., I’m like, ‘Dude, that’s too late!'”

He says he knows “no one really loves the treadmill,” but sometimes it’s a necessary tool to get your training in if things are too hot or too humid outside.

“I tell my athletes not to be a hero,” he says. “Don’t go running outside if it’s oppressively hot. Either get up before the sun or, if you can’t do an early wakeup, stay inside for your workout.”

To learn more about Lentzke and his triathlon coaching services, visit his website here.

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