11 Tips for Running in the Heat, According to Experts

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If you’re an avid runner, few things can stop you from lacing up your sneakers and heading out for a run. In fact, if you’re super committed, you’ve most likely invested in all sorts of weather-protected running gear so that you can perform your running workout in the rain or shine. While most weather circumstances are safe for running, it’s important to be especially careful on hot days. 

Even the most advanced and experienced runners can run into challenges when running in the heat of summer, especially when the temperature is above 98.6 degrees, or the average normal body temperature, and the humidity is above 70% to 80%.

“Running in the heat puts extra stress on the body to ramp up its natural cooling system,” explains Roger E. Adams, PhD, doctor of nutrition and owner of eatrightfitness. “For a beginner, or runner that is inefficient, their body must work harder to cool off during running, so the more in-shape you are and conditioned as a runner, the better you can cool off and handle the heat.”

Below, we share some of the best advice for how to run in the heat as shared by fitness experts. Learn what to do when it is hot outside, including how to make the most of your runs and still stay safe.

Pay Attention to Humidity

Research shows that running in the heat, especially for those not adapted to doing so, can make it very difficult for your body to maintain its core internal body temperature, which is necessary for optimal bodily performance and survival. This, coupled with other physiological strain, including a rise in heart rate, can impair your endurance and exercise capacity.

While any temperature that really makes you feel too uncomfortable may be too hot for running, the Road Runners Club of America places the cap at 98.6 degrees. It’s also important to point out that the heat isn’t always the top concern. Humidity is also a predictor of whether or not it’s safe to run outside. 

“When running in a humid climate, the additional moisture from the atmosphere sticking to your skin limits your body’s ability to cool off by interfering with sweat evaporation, which is how we cool off,” says Dr. Adams. “The moisture in the body, under the surface of the skin, absorbs the additional heat caused by a hot environment, elevated temperature due to exercise, fever, anything that may cause your body temperature to rise and is then pulled to the surface of the skin so the evaporation process can take place.” 

When this evaporation is limited, due to humidity, Dr. Adams warns that the body can quickly overheat. For this reason, he recommends paying equal, if not more, attention to the humidity levels as you do the outdoor temperature. And in circumstances where both high temperature and high humidity are combined, recognize that it is not a safe running situation.

Practice Running in Hot Weather

No matter the type of exercise you’re performing, or the conditions in which you are performing this exercise in, you will have an easier and safer experience if you’re properly trained, notes Meghan Kennihan, NASM-certified personal trainer and USATF Run Coach. One side effect of physical fitness, according to research, is an increase in blood plasma levels.

Kennihan notes that this increase plays an important role in the cooling process. If you’re well-trained to run in the heat, your body is going to have an easier time coping with the heat. She recommends doing your workouts and training outside rather than in the comfort of an air-conditioned gym so that you are better-adjusted for warmer temperature levels, especially if you plan to exercise outdoors in the long-term.

Adjust Your Expectations

It’s important to acknowledge that even the most heat-acclimized athlete will suffer performance loss in hot conditions. For this reason, Kennihan recommends finding ways to adjust both your expectations and your workouts to reflect the hot conditions. 

“Slow down, listen to what your body is telling you, and know how the hot and humid conditions affect your recovery, so that you can monitor your subsequent workouts and the progression of your training plan,” she says. “The heat will make your workouts harder on your body, so it is smart to use some extra recovery modalities after especially hard days such as electrolyte replacement drinks and foam rolling and gentle stretching.”

Hydrate Before, During, and After Your Run

Proper hydration is critical whether or not you’re exercising, but even more so when you’re in the midst of physical activity because your body releases more fluids through sweat. This is even more exacerbated by hot temperatures, notes Kennihan.

She advises all of her team members to drink before, during, and after their workouts. Likewise, the Road Runners Club of America recommends consuming at least 10-15 ounces of water 10 to 15 minutes before you set out to run and drinking water every 20 to 30 minutes during your run. 

Dress Appropriately

Just as you would dress warmly, likely in layers, if you were to run in cold weather, it’s important to take the same level of precautions when running in hot weather. Samantha Clayton, personal trainer and group exercise coach through the American Fitness and Aerobics Association (AFAA), recommends reaching for light-colored fabrics that are breathable.

Sweat-wicking fabric will give your body every opportunity to maintain an adequate internal temperature. She also recommends against wearing hats and instead suggests opting for visors because they are less likely to lead to overheating. 

Avoid Running on an Empty Stomach

While you certainly don’t want to over-eat before a run—especially when it’s hot outside—Clayton warns against running on an empty stomach, as it can place an even greater stress on the body. 

“​​The body requires additional energy to cool down in the heat while exercising," she says. "So it’s a good idea to top off your fuel tank with a pre-run snack or sports drink that has carbohydrates in it. The carbohydrates will help keep you energized for a longer period of time throughout your run.”

Seek Out a Shaded Route

If possible, consider taking a shaded route on a hot day so that you’re less exposed to direct sunlight. Timothy Miller, MD, Orthopaedic Surgeon and Sports Medicine Specialist at The Ohio State University Wexner Medical Center in Columbus, Ohio, recommends sticking to shaded loops or paths or even a metro park.

You could even consider a trail with a creek or two that you can run through and splash some cool water onto your body during your workout. The key is to find an area that does not have a lot of direct sunlight in order to keep your body as cool as possible.

Stay off the Black Top

In blazing summer heat when the sun is out the temperature of a black top road or street (especially those in unshaded areas) can reach well over 100 degrees, notes Dr. Miller. For this reason, he recommends running on grass, cinder, or dirt trails as opposed to concrete or pavement. These surfaces which do not absorb the sun’s heat as readily are a much cooler and safer option. 

"Regardless of the surface on which you train, investing in something as simple as a cooling towel, an ice collar, or even a small kiddie pool filled with cool water and ready for a quick plunge after the run can bring your body temperature back to a safe level during and after a hard training session in the heat," he adds.

Track Your Conditioning With a Smart Watch

Smart watches are useful for more than just telling the time and texting your friends and family. In fact, they can be useful accessories that aid your exercise routine—especially if you plan on running in inclement conditions. Alexandria Williams, Road Runners Club of America’s certified running coach and director on the board of the National Black Marathoners Association, is a big fan of watches that track heat acclimation. 

For instance, the Garmin Forerunner® 255 smartwatch series takes into account how your body is responding and adjusting to the outdoor temperature and is displayed in a percentage indicating climate acclimation.

“It's a great indication of how your body will adjust to being in the current temperatures,” she says. “It takes a lot of time, and I enjoy the small ways it shows me that I am improving each week.”

Protect Your Skin

As an avid outdoor runner, you should be wearing a sunscreen with at least a 30 SPF year round, but especially during the warmer months of the year, when the sun is at its strongest, according to Marisa Garshick, MD, a dermatologist at Medical Dermatology & Cosmetic Surgery (MDCS) in New York.

Dr. Garshick recommends applying sunscreen at least 20 minutes prior to heading out for a run and trying to avoid the hottest times of the day, which tend to be between 10 a.m. and 3 p.m. You also can select gear that is designed to block the sun as well. And, don't forget to protect your eyes.

Know When to Stop

If you are going to run in the heat, it’s important to be aware of the signs of heat exhaustion which can develop quickly within minutes, or gradually over several hours or days, explains Jennifer Sobel, NASM-certified personal trainer, professional dancer, and creator of The Belly Dance Solution. 

“If you feel disoriented, confused, dizzy, or nauseous, stop immediately, find a cool place and remove as much clothing as possible,” she says. “If you can, pour some cold water on yourself. If your symptoms don’t improve within 30 minutes, seek help immediately.” 

Safety Tips

According to the Road Runners Club of America it is important to be safe when running in hot weather. Here are some things to keep in mind.

  • Understand heat index dangers.
  • Dress for the weather.
  • Wear sunscreen.
  • Avoid dehydration by pre-hydrating and carrying water.
  • Know the signs of heat illness and heat stroke and get help when needed.
  • Talk to a healthcare provider about your medical history before running in the heat.

A Word From Verywell

All in all, running in the heat can be achieved safely and efficiently, but it's important to be prepared, be smart, and to be aware of other elements aside from the temperature. Pay attention to humidity levels as well as how your body is responding and make adjustments as needed.

You also should take steps to hydrate and fuel your body as well as know the signs of heat exhaustion. In those situations, it is important to get medical attention right away. Of course, with the right know-how and the right gear, you'll be able to enjoy an outdoor run in hot weather in a safe and effective way.

Frequently Asked Questions

  • Is it bad for you to run in the heat?

    While running in heat higher than your internal body temperature (98.6 degrees) can be dangerous, it’s important to not just look at the heat when determining if it’s safe outside. This is because running in the heat with low humidity is completely different from running in the heat with high humidity.

    If you are a conditioned runner who is used to running in the heat—and that heat is coupled with low humidity—you should be OK running in the heat. However, you may still have trouble if the heat is above your internal body temperature. Listen to your body and don't be afraid to stop running and do some other type of training that day like swimming or weight lifting.

  • How much water do you need when you are running in the heat?

    When you exercise in the heat, your body loses more water than it would if you were exercising in colder temperatures, according to research. For this reason, it’s important to hydrate adequately. Start out with 6 to 8 ounces of water or hydration beverage before you even run and continue to consume 4 to 8 ounces every 20 minutes you are training. 

  • What are the signs of heat exhaustion?

    Symptoms of heat exhaustion, also known as heat stress, often include nausea, dizziness, light-headedness, vomiting, headache, increased thirst, weakness, excessive sweating, muscle cramping, and reduced urination. You also may have a high body temperature.

7 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Road Runners of America. Run safe in hot weather.

  2. Racinais S, Alonso JM, Coutts AJ, et al. Consensus recommendations on training and competing in the heat. Br J Sports Med. 2015;49(18):1164-1173. doi:10.1136/bjsports-2015-094915

  3. Stautemas J, Van Kuilenburg ABP, Stroomer L, et al. Acute aerobic exercise leads to increased plasma levels of r- and s-β-aminoisobutyric acid in humansFront Physiol. 2019;10:1240. doi:10:1240.10.3389/fphys.2019.01240

  4. Van Cutsem J, Roelands B, De Pauw K, Meeusen R, Marcora S. Subjective thermal strain impairs endurance performance in a temperate environment. Physiology & Behavior. 2019;202:36-44. doi:10.1016/j.physbeh.2019.01.011

  5. Run Safe in Hot Weather. Road Runners Club of America. July 1, 2022.

  6. McDermott BP, Anderson SA, Armstrong LE, et al. National athletic trainers’ association position statement: Fluid replacement for the physically active. Journal of Athletic Training. 2017;52(9):877-895. doi:10.4085/1062-6050-52.9.02

  7. National Library of Medicine. Heat illness.