Running and racing in the heat is never easy. Whether you’re running in a dry or humid climate, your body temperature runs higher than normal, you sweat more, work harder and run slower in hot weather. It’s not only a physical burden, but also a mental one, knowing that you might have trained for several months for a certain pace only to have your goal time thrown out the window for a more realistic pacing strategy appropriate to the conditions.
If you have unseasonably warm conditions to greet you on race day, you’ll have to adjust your goals, but don’t despair: There are plenty of steps you can take to maximize your performance.
Replace Lost Fluids
In hot weather, your body self-regulates its core temperature through a variety of means. Heat is moved from muscles and released through the skin by convection. Heat also leaves the body in water vapor as a runner exhales and is dispersed via sweat, a process that cools the skin and releases heat during evaporation.
But each of those processes works better when you’re optimally hydrated. The fluids you ingest before and during a race—both in the form of a carbohydrate/electrolyte beverage and water—act as conductants that help transport heat. The more fluid or water you have in your body, the more heat you can remove. If you get dehydrated—and thus have less fluid in your body—you limit the body’s ability to remove heat and thus limit your performance.
The key to maintaining performance in hot conditions is sufficiently replacing the fluids and electrolytes you lose while you’re running. Although there are recommended guidelines for consumer liquids during a run or race—roughly 4-6 oz. of carbohydrate/electrolyte beverage every 20 minutes or so—the amount of fluid needed varies greatly among runners.
Knowing your sweat rate is one way of estimating how much fluid you’re losing at race pace under those temperature conditions. If you have a high sweat rate, you might need to replace electrolytes more often than you need to take in carbohydrates. Practicing your fluid replacement strategy ahead of time is important to maximizing performance in warm and hot conditions, especially because the body can more quickly absorb electrolytes if they are consumed without carbohydrates.
Start Hydrating Early
The process of becoming optimally hydrated before a race doesn’t happen overnight. It actually needs to start about three days before the event. In the tapering phase of your training, your body will store more water and electrolytes, but you still need to drink fluids with electrolytes and not just water. In the days before a race, you can drink water with meals because there will be plenty of electrolytes in your food. However, outside of your mealtime, hydrate with electrolyte drinks so you can retain fluid. Also, if you’re feeling thirsty or your urine has a moderate to strong yellow color at any point during the days before your race, you’re too dehydrated.
If you have a moderate to very high sweat rate, you can benefit from taking in extra sodium a day before the race. The increased sodium levels in the blood prompt your brain to drink more fluid to balance out the sodium levels. Continue with your normal pre-race nutrition regimen, and add 3,500-5,000mg of sodium 18-24 hours before competition to your diet by periodically taking salt capsules or sodium-packed snacks the day before the race. With the elevated sodium level in your blood, your brain will prompt you to drink often before and during the race, and help keep your electrolyte levels high during competition.
Eat A Cool Breakfast
You can keep your core body temperature as low as possible by eating a cool breakfast with foods that will produce a low thermogenic effect. Some people like to eat a plain bagel with peanut butter on it, and while that’s fine, it’s going to be a little harder to digest—and therefore have a higher thermogenic impact—because of its fat content. Drinking a cold smoothie or eating chilled low-residue fruit (grapes, cantaloupe, plums, apricots, melon, peaches, watermelon, applesauce) will help keep your core temperature low. Eating a piece of white toast with jam is OK, but avoid raw and dried fruits, raisins and berries and prune juice.
Reduce Your Warmup
If warm temperatures prevail before your race, do as little as possible before you get to the starting line, including a very limited warmup session. At that point, it’s really more about just activating your muscles, so you don’t necessarily need to run at all. Typically, I have runners do some easy sports band stretching just to remind their muscles that they’re getting ready to move. If you let the race warm you up, you can ease into your race paces. You should minimize the amount of time you’re out in the heat and in the sun prior to the start of the race.
Start Slower And Adjust Your Goals
For hot races, it’s important to readjust your race plans by starting slower than what you had planned and setting your original time goals aside. You’re bound to run slower in hot conditions, but that doesn’t mean you can’t run hard and turn in a competitive effort. I typically tell runners to add 20 seconds to the per-mile pace they were planning to run as a safe estimate that will give them the best chance of finishing, as well as competing well in the second half of the race. The runners who insist on going out fast on their target pace are the runners who wind up stalling out.
Lower Your Core Temperature
Most people don’t have access to an ice vest (like Deena Kastor did before the start of the 2004 Olympic marathon), but you can get a lot of benefit by keeping bags of crushed ice on your body before a race. Keep the ice around your waist or simply lie or sit on a bag of ice will simulate the effects of an ice vest. Holding something cold in your hands can help lower your temperature a little bit, but it can also tell your brain you are comfortably cool, able and ready to race at a high level.
Drink Early And Often
Once the race starts, drink fluids at every aid station, but don’t make the mistake of drinking only water. You’ll want to take in 200mg of sodium and some potassium with every 8-12 oz. of fluid during a race. As long as you’re taking in some kind of electrolyte drink, you’ll avoid the dangerous situation of hyponatremia. Drink at every aid station and even slowing down to drink two cups of fluid, one with electrolyte drink and one with water, or maybe two cups of electrolyte drink. You can also benefit by carrying a water bottle from the start of the race with an electrolyte drink in it or a dissolvable electrolyte tab like Nuun.
Sports nutritionist and exercise physiologist Krista Austin, Ph.D, has been a consultant to numerous U.S. Olympic runners and triathletes.
Originally published July 2018