I had just returned from my first long training run and instead of giving myself a high-five, I felt more like I was on the losing end of a MMA fight. I just had my ass kicked by the steaming heat of summertime. To be honest: It’s my own fault. I jogged out the door hungry and thirsty (from the previous night’s happy hour) at 9 A.M. I wore black leggings and forgot water. Basically, I was completely unprepared.
I’m training for my first-ever marathon—I’ll be running the TCS New York City Marathon thanks to getting a free slot on the New Balance team. And sure, it will land on a (hopefully) crisp November day in New York, but my training has started in the middle of summer and I nearly passed out on my first long run. Oh, and did I mention that I live in New Orleans?
After that run, I wondered: Is it possible to train for a marathon in one of the most hot and humid cities in the U.S.?
First, I decided talk to an expert on athletic performance in hot environments, who could help me understand why my run felt so unbearable.
I reached out to Rebecca L. Stearns, Ph.D., the chief operating officer at Korey Stringer Institute within the department of kinesiology at the University of Connecticut, who told me that the reason heat and humidity impact us so much during exercise is because our bodies already produce a lot of heat while working out as a result of the mechanical processes happening inside our muscles and body when we use energy. (They call it “burning” energy for a reason.) Stearns explained that sweat—specifically, the evaporation of sweat off the surface of our skin—is the release of this heat and the main way the body cools itself during exercise.
When the environment around us is also very hot, it makes it harder for our bodies to cool off through this process. “[Environmental] heat becomes dangerous because it can result in a scenario that we refer to as uncompensable heat stress, where your body is gaining heat faster than it is being dissipated,” said Stearns. So even if your cooling mechanisms are working, the external heat can throw you over the edge and be too much for your body to handle.
To make matters worse, humidity in the air makes it harder for sweat to evaporate. “The more saturated (with humidity) the air is, the less availability there is for evaporation, meaning it will just drip off the skin, which doesn’t allow the body to cool,” Stearns said.
Being in New Orleans, I’m faced with both heat and debilitating humidity. In August, most locals retreat to air-conditioning or spend the day in a swimming pool. How would I ever manage to prep for a marathon?
I’d just have to get my body used to training in the heat. But how?
Luckily, New Balance hooked me up with a remote running coach, John Honerkamp, founder and CEO of J. R. Honerkamp Consulting & Coaching, who I immediately reached out to after that first run. Honerkamp said that while your body can acclimate to running in the heat over time, it can be difficult when you first start. “I always say I am pretty good at running in the heat eventually, but out of the gates I struggle,” he said. This made me feel a little bit better.
So then, how could I get my body acclimated enough that my runs feel more bearable? Stearns said that generally, it takes most people approximately 10 to 14 days of being active in the heat to get adjusted to it. Of course, this all varies by person and the intensity and frequency of activity, and different adaptations—like changes in perceived exertion, sweat rate, blood volume, and heart rate—happen at different points during that rough time frame.
Honerkamp also suggested that I start by slowing down my pace. Considering that I run a 13-minute mile, I tell him I’m wondering if I should speed walk. But he assured me that not having a time goal for my first marathon is a good thing, and that it’s more important to focus on the effort than speed.
So, for the next two weeks, I focused on slower and shorter runs. I also shopped for a new running wardrobe.
Honerkamp told me that less clothing is better in the heat, but that I should add a hat specifically for running (to protect myself from the sun) and wear sunscreen. Stearns said that comfortable and loose, light-fitting clothes will allow air movement across my skin which helps sweat evaporate.
Armed with new information, I purchased a pair of '80s-style biker shorts and a breathable white hat, and applied broad-spectrum SPF. It’s true, clothing (or lack thereof) made a difference and after a few short runs, the heat actually started to feel less oppressive.
Before my next long run, I asked Stearns what precautions I should take to stay safe.
Longer duration exercise can provide a greater opportunity for your body’s temperature to rise to an unsafe level, Stearns said. She suggested I give myself opportunities to rest, rehydrate, and adjust the intensity depending on how I feel. These things are “all important to avoid potentially dangerous body temperature elevations.”
I asked Stearns about what warning signs may signal I’m starting to overheat. “You might start to feel hot, unusually tired, irritated, or your mental functioning might decrease (feeling confused or disoriented),” she said. The symptoms of severe dehydration are similar, so it’s important to listen to your body and take a break and rehydrate if you start to notice any of these signs.
In one of my daily training emails from Honerkamp, I got a tip to weigh myself (naked) before and immediately after the run to calculate my sweat rate. The goal is to lose no more than 0-2 percent of my initial body weight, he said. So, if I were to lose more than 2 percent of my initial body weight, that means I’m not taking in enough fluid during the run. Quick note: You don't have to weigh yourself to make sure you’re hydrating enough. It's just a tool that some experts suggest, and that comes in handy when you're training for long periods of time in the heat.
But you probably don’t need to overthink it. Most experts (including Stearns) say, quite simply, that healthy adults can usually stay hydrated by listening to their bodies and drinking water when they feel thirsty. “Generally, if you have readily available fluid, drinking to thirst will keep you at a safe hydration status,” Stearns told me. It may not be the best solution, though, if you’re running in a race and only have limited scheduled breaks for water. That’s because when you’re forced to delay your fluid intake, you may end up not drinking as much as you truly need once fluid is available. A simple solution is to just bring water with you on a training run or during the race, Stearns said, so that you are able to drink whenever you feel thirsty. If that’s not possible, though, Stearns said that calculating your sweat rate like Honerkamp suggested (here’s an online tool you can use) is actually the best way to make sure you’re drinking enough when you're working out hard in the heat with infrequent access to water.
Stearns added that while the best amount of fluid to drink will be different for everyone, generally the stomach will handle small doses of fluid at greater intervals better than lots of liquid all at once.
Also, I’d be remiss to not mention that properly hydrating also means drinking before and after a run, not just loading up on it once you’re unbearably thirsty. So, I decided to skip Friday happy hour and, instead, pre-hydrate leading up to my long Saturday run.
On the first day of August, I set out on a 10-mile run, during which I felt much more comfortable in the heat—and with the idea of slowing down and taking breaks.
I left my house at 6 A.M., and stopped at the park’s water fountains along the way for small sips of water. There were times when I felt like I was jogging in cement, but my body didn’t hate me. In fact, I had a reserve of energy and sprinted the last block home. Did I mention that the heat index was at 109 degrees?
Post-run, I celebrated with lunch beers. Of course, less alcohol is better when you’re trying to keep yourself fully hydrated, but I figure that that doesn’t mean I can’t enjoy a drink or two when I really want it. (Keep in mind that I’m not a doctor or a dietitian and I’m only making choices for myself. If you’re wondering if you can drink after you have a tough workout, check with your doctor.)
By my third or fourth long run, I was way more comfortable in the heat and kept my hydration in check. (I’m sure that my improving cardiovascular fitness also plays a part in making my runs feel less miserable.)
I’ll be honest, after most long runs, I still want nothing more than to dunk my body into a cold pool of pamplemousse La Croix and sleep for an hour—but the long distance feels doable and occasionally enjoyable. Plus, there’s always happy hour at the finish line.