7 safety tips for working out in the heat

You’re power walking along a path when you realize the temp has climbed close to 100 degrees Fahrenheit (F). Even though you’re dressed for the heat and are carrying water, is it safe to exercise outdoors when the temperature soars?

Working out in the heat puts additional stress on the body and exposes you to risks not present during cooler temperatures. To decrease your chance of overheating—or worse, having a serious complication, such as heat stroke, take extra measures to stay safe when exercising outside. 

The benefits and dangers of working out in the heat 

Some people prefer exercising in the heat. They know it takes less time to warm up when it is warm outside, and stiff muscles and tendons feel better in the warmth, compared to in the cold. 

What’s more, some people think training in the heat yields better flexibility and burns more calories. However, there aren’t any studies to know just how many more calories you burn working out on a hot day versus a cooler day.

However, the risks of heat-related illnesses are real—and these risks rise as temperature and humidity increase. 

What are heat-related illnesses? 

Heat related illnesses are ailments caused by overheating. Body temperature is maintained within a narrow range. The body balances heat load with heat dissipation. The body’s heat load is from both metabolic processes and from absorbing heat from the environment. When your body can’t cool itself down effectively by sweating in hot conditions, your core body temperature rises. This rise in core body temperature can lead to the following health problems.

Heat cramps

Heat cramps are the mildest heat-related illness. The symptoms include:

• Painful, involuntary spasms usually in the arms, legs, or abdomen
• Muscle pain in arms, legs, or abdomen
• Cool, moist skin
• Normal or increased (but not above 104 degrees) body temperature 

Hot environmental conditions and dehydration lead to heat cramps. Heat cramps are painful muscular cramping, usually occurring in big muscle groups, that occurs during or after exertion in hot environments. The cramping feeling may be from an electrolyte imbalance from sodium depletion due to too much sweating.

Heat exhaustion

“Heat exhaustion is when someone feels sick due to loss of salt and water from heat exposure,” says Michael Chen, MD, a physician at One Medical in Portland, Oregon. “People may feel their heart racing, be nauseated, sweaty, or weak, but their body temperature usually stays below 104 degrees Fahrenheit.” 

Heat exhaustion typically occurs with prolonged exercise in hot conditions accompanied by dehydration and overexertion. Symptoms include:

• Headache
• Nausea or vomiting
• Fatigue or weakness
• Irritability
• Dizziness
• Heavy sweating, at first
• Thirst
• Decreased urination

If you experience these symptoms, go to a cool environment and cool your body temperature by removing unnecessary clothing (like shoes and socks), take small sips of cool water, apply cool compresses, and take a cool shower. Seek medical attention if symptoms don’t improve. 

Heat stroke

When the thermometer goes above 104 degrees, outside exertion gets risky. “That means your body is overheated and you’re experiencing heat stroke, a serious condition that requires emergency medical treatment,” Dr. Chen says.

Heat stroke, the most serious heat illness, is the body’s inability to regulate its temperature. Your core body temperature can quickly rise, within 10 to 15 minutes. Symptoms include:

• Disorientation
• Confusion or slurred speech
• Hot, dry skin
• Shallow breathing
• Seizures
• Body temps over 103°F
• Lack of sweating

It can be life threatening and requires immediate medical attention. “If left untreated, it can cause significant damage to the brain, heart, and kidneys,” Dr. Chen says. “The longer treatment is delayed, the worse the damage can be. That’s why it’s so important to know the signature symptoms of heat stroke.”

7 ways to exercise safely in the heat

When is it too hot to run? Are summer workouts okay? After taking proper precautions, you can safely do your cardio during the summer. Here’s some tips to stay safe when working out in the heat:

1. Work out when it’s cooler. 

Opt for early mornings or early evenings when it’s cooler outside. Many phone apps show the temperature at each hour of the day, so you can schedule appropriately. When the temperature soars over 100 F, or there is a heat index of 7 or greater, skip your outdoor workout or move it indoors. 

“The hotter it is and the higher the percentage of relative humidity, the greater the risk to your health,” says Snehalata Topgi, MD, an emergency medicine physician and event medical director at ParaDocs Worldwide, an events medical services company. “For example, 71 degrees with high humidity can be dangerous because your body cannot evaporate the sweat. And sweating is how our bodies cool.”

2. Take a cold shower. 

Before you start working out, consider taking a cold shower. To stay cool during your workout, skip the blow dryer after taking a pre-workout shower and exercise with wet hair instead. 

3. Drink the right liquids to hydrate. 

Staying hydrated on a hot day means drinking water. Schedule hydration breaks. If you plan to exercise for more than 60 minutes, you may also want to change your liquid of choice to a sports drink. Research finds that functional sports drinks may be better than water for prolonged exercise and performance in hot weather. Flavored water has been shown to increase fluid consumption, so try adding your favorite flavor.

Sports drinks help replenish your body’s sodium, potassium, and electrolytes. Sodium is a key ingredient in keeping cool on a hot day because it helps your body retain water. “Your water needs will vary depending on your activity level and geographical location, but the Institute of Medicine recommends a daily total of 3.7 liters (15 cups) for the average adult male and 2.7 liters (11 cups) for the average adult female,” Dr. Chen says.

4. Wear light clothing. 

Wearing light colored, moisture-wicking clothing can help pull sweat away from your skin to help keep you cooler. Fabrics like cotton, bamboo, and Tencel are breathable and have water-wicking fibers that keep you drier. Colors like white, gray, beige, tan, and soft pastels work well for keeping cool as the temperature rises, avoid dark colors as they attract and hold heat.

5. Eat small meals more frequently. 

When it’s super-hot outside, eat a smaller meal before and after workouts to help decrease nausea and cramps. Don’t eat too much before a hot workout as your body will divert blood to the intestines and can make you feel fatigued faster.

6. Check in on your body temperature. 

Frequently check your body temperature. While some people feel fine at temps over 101 F during an afternoon summer workout outside, others will start to feel the effects of heat-related illness. If you feel overheated, fatigued, dizzy, weak, or faint, stop immediately. Get inside, cool down, put your feet above your heart, drink plenty of cold liquids, and rest to prevent developing heat-related illness. “Buy insulated bottles or packs to keep ice packs or your drinks cold,” Dr. Topgi suggests. “Try applying that to your wrists or your necks to cool down.” 

7. Learn your medical risks

Certain medical conditions make you more prone to heat-related illness, such as high blood pressure, diabetes, heart problems, or kidney issues. Additionally, certain prescriptions can make exercising in the heat even more dangerous.

Some types of medications can remove salt and water from your body, causing dehydration. If you take medications that cause dehydration, exercising when it’s hot can lead to severe dehydration and other heat-related illnesses more quickly than if you were not taking them. You may be more prone to a heat-related illness if you take diuretics, laxatives, oral diabetes medicine, chemotherapy drugs, or lithium for bipolar disorder.

Other medications reduce your ability to sweat. Some medications that cause heat intolerance include certain migraine and allergy medications, vasoconstrictors, and tricyclic antidepressants. These can raise your risk for heat-related illness by preventing the dispersion of heat through sweating.

”Be cautious if you’re at an increased risk or take medications that can increase your risk—talk to your provider to understand how to manage your risk,” Dr. Chen says. Pay special attention to exercising in hot weather, getting the proper hydration, and knowing the signs of heat-related illnesses to gauge how you feel while exercising outdoors. 

When the temperature rises, be sure to take the proper precautions to avoid heat-related illnesses. Carry water or a sports drink, wear loose, light-colored clothing, and check in with yourself once you begin exercising so you can recognize when your body is overexerted.