13 Tips for Running in the Heat from Runner's World
Don’t be surprised if you feel a little extra sluggish when temperatures soar. When it’s hot outside, the brain tells the muscles to relax in order to keep the body’s core temperature low, and the process of sweating to stay cool diverts blood away from the muscles. Add allergies, dehydration, and longer daylight hours to the equation, and it’s tempting to take a vacation from training until cooler temperatures prevail. But your performance doesn’t have to suffer just because the mercury’s on the rise. Here are Runner’s World’s best tips for beating the heat.
1. Run before the sun.
Head out before sunrise; it’s the coolest time of day. Your body’s core temperature is at its lowest right after you wake up, which means it takes longer for your body to overheat. If you can’t run in the morning, work out as late in the day as possible. Although the sun is highest in the sky at noon, the earth's surface heat peaks between 3 p.m. and 5 p.m. For a cool long-run adventure, get some friends together and do your long run after dark.
2. Check the heat index before you go out.
It’s not just the heat; the humidity will take a toll, too. Moist air slows down your body’s ability to cool itself through sweat. The heat index combines temperature with relative humidity to determine the apparent temperature—how hot it actually feels—and the National Weather Service issues a heat advisory when that hits 105° F. Be sure to check the temps and the heat index before you go.
3. Wear the right gear.
Go for light-colored, loose-fitting technical clothing and a visor. Unlike cotton, technical fabrics wick away sweat and dry quickly, meaning you won’t feel weighed down by your sweat-soaked T-shirt. Light-colored clothing reflects heat, and a loose fit lets air circulate. Hats trap heat; visors will keep your head cooler while still shading your face from the sun. Wear apparel with a UPF-rating (ultraviolet protection fabric), which means it shields skin from UVB and UVA rays. For tips on what to wear in any weather, check out our “What Should I Wear?” tool here.
4. Slather on the sunscreen.
Use a product with an SPF of at least 30, and one that protects against UVA and UVB rays, the two most damaging forms of ultraviolet light. Rub on the sunscreen at least 20 minutes before you go out, and reapply every two hours after you’re out—even if it’s a sweat-proof formula. For reviews of runner-friendly sunscreen, click here. If you have questions about any unusual markings or moles, which can be precursors to melanoma, see your doctor.
5. Cool off before your run.
Lower your core temperature before you work out by precooling with an icy slushy or a jump into the pool. Research has shown that runners who slurped an icy slushy before a sweltering run lasted an average of 10 minutes longer than participants who gulped a cold drink.
6. Don’t get hot under the collar.
Cooling the head and neck will lower your core temperature in a hurry; that’s because the blood flows close to the surface of the skin on the neck. Roll a row of ice cubes in a bandana like a burrito and tie it around your neck. Or, soak a sponge in cold water, place ice cubes on top, and put a hat on over both. Both will send cool water trickling down your neck.
7. Reset your race goals.
You can’t expect to put your training to the test when the temperature is soaring. So put your PR hopes on hold if race day turns out to be a scorcher. Research has proven that the optimum temperature for running a marathon is 54° F. Every seven degrees above that, your overall time slows by a minute or more. Plan another race in four to six weeks to try again. If your marathon plans get sizzled, this article details how to train for a second-chance race.
8. Know your sweat rate.
Some people sweat more than others. Some people also lose more minerals in their sweat than others. The best way to gauge how much fluid you need per hour on the road is to take the sweat rate test, which involves simply weighing in naked before and after a one-hour run. For every pound of weight lost, drink 16 ounces of fluid per hour while you run. To find out more about measuring your sweat rate, click here.
9. Get in the drinking habit.
If you don’t have a scale handy, here are a few general rules to follow when it comes to drinking.
Every day: Each day, drink the equivalent in ounces of half your body weight. For instance, a 150-pound runner would aim for 75 ounces of water each day. You'll know you're well-hydrated when your urine is pale yellow; if it’s dark yellow or the color of apple juice, you’re dehydrated.
Before you go: Have eight to 16 ounces one to two hours before a run. Fifteen to 30 minutes before going out, have at least four to eight ounces of fluid.
On the road: If you haven’t taken the sweat rate test, when you’re out for more than an hour, aim for 14 to 20 ounces of fluid per hour.
After you’re done: Drink eight to 24 ounces of fluids to rehydrate when you return.
10. Go for the strong stuff.
When you’re going long, or if it’s a particularly hot day, have a sports drink with sodium and other electrolytes, not just plain water. Look for a drink that contains 25 to 50 grams of carbs, 230 to 345 milligrams of sodium, and 40 to 100 milligrams of potassium. If you’re feeling queasy from drinking, fruit and these other cold recovery treats make good nonliquid alternatives. Read this article to learn more about which drinks are appropriate for different kinds of workouts.
11. Map out hot-weather routes.
Make sure your summer runs have plenty of shade and places to stop for water. Neighborhoods tend to have more shade, and often they have sprinklers to run through. Run in a park with water fountains or a place to stash extra water, or map out a route that passes convenience stores (just be sure to carry a few dollars with you). Better yet: Map out a loop from your house so you can circle back home to refill and change your clothes if you get drenched. Pick out a new route from one of thousands in the Runner’s World’s Routefinder, or map out a new one of your own.
12. Watch the pollen.
Pollen from ragweed and other grasses is common during the summer, so runners with allergies are likely to experience itchy eyes, sneezing, and congestion. Pollen counts are often highest between 5 a.m. and 10 a.m., so if you suffer from allergies, you might want to go out later in the day. Check pollen.com for updates, or hit the treadmill. Shower right after you run; pollen that settles on hair, clothes, and eyelids can continue to trigger reactions. If you wear contacts, you might be better off putting on your glasses to shield your eyes from the pollen. Rain often removes pollen from the air, so you may want to go out right after a storm.
13. Adapt, adapt, adapt.
If your race is bound to be hot, you can acclimate your body by gradually exposing yourself to warm environments. Do your main workouts before 10 a.m. or after 6 p.m. (the coolest parts of the day), but go for a 15- to 20-minute light run or walk in the heat of the day. Increase the intensity and length of your hot workouts by five to 10 minutes over the course of two weeks until you adjust.
This article was written by Coach Jen Van Allen of Runner’s World, the most trusted source for running information for more than four decades now with a full selection of training plans for 5-Ks, 10-Ks, half-marathons, marathons, and more for sale in the TrainingPeaks store. Plans are built according to the training principles that have proven to be most effective by millions of runners, and they include our best tips on training, nutrition, motivation, and injury-prevention.