June 25, 2026
Warm weather and sunshine can be great motivators to exercise outside. But before you lace up your sneakers, remember the summer months often come with scorching temperatures and high humidity, factors that affect how your body handles physical activity.
"When it's hot outside, things that feel easier in cooler temperatures may feel more challenging," says Allyson Sanders, MD, a family and sports medicine doctor at MU Health Care. "Your heart and muscles need to work harder in high heat, and there are a lot of physiological changes that affect how your body performs."
The good news is that exercising in the summer heat can be completely safe — you may just need to tweak your workouts slightly and take a few precautions. Dr. Sanders shares five things to do to stay active and safe in the hot months of summer:
1. Plan Your Exercise Around Heat
The bummer about summer is that the heat and humidity can feel unbearable in the midday hours. Switching your workout time to early morning or late evening ensures you'll be exercising in cooler temps, even if the humidity is still high.
If you must exercise during the day, try to stay in shaded areas whenever possible. Run on a wooded trail instead of the high school track, for instance. Shade can lower the temperature by 15 to 20 degrees.
"It's important to stay flexible with your exercise," Dr. Sanders says. "If it's dangerously hot and the heat index is extremely high, you may need to exercise inside that day."
2. Hydrate Before, During and After Exercise
Hydrating may be the single most important thing you can do when exercising in the heat, according to Dr. Sanders. Drinking a few sips of water after a workout is not enough. Your body needs to be hydrated before, during and for hours after your workout.
"Most people only hydrate when they feel thirsty," Dr. Sanders says. "That can put you behind the ball. You can be well on your way to dehydration when thirst sets in."
Proper hydration keeps your cardiovascular system functioning well. It can also help with recovery and reduce muscle cramping. Dr. Sanders recommends:
- Start early: Hydrate at least an hour before exercising. If you have a long or intense workout planned, start hydrating the day before.
- Bring water with you: Take a sip or two every 10 minutes while working out.
- Replenish: Consider adding electrolytes to your water after a strenuous workout, especially if you are a salty sweater.
- Eat hydrating foods: Supplement your hydration efforts with foods that have high water content, such as melons, tomatoes, lettuce and cucumbers.
3. Let Your Body Adapt to the Heat
The body gets used to heat and humidity relatively quickly — sometimes in as little as two weeks, says Dr. Sanders. But not giving yourself time to adjust could stress your body.
Research shows that once your body acclimates to a seasonal change, you can expect:
- Increasing sweat rate
- Less salt in your sweat
- Reduced resting core temperature and heart rate
"When you start sweating more quickly, it means your body is getting used to the heat and cooling more efficiently," Dr. Sanders says. "But sweating quickly and profusely should also cause you to hydrate more."
Start slowly, with lower intensity workouts and short sessions. Gradually increase your body's exposure based on how you feel.
4. Recognize the Signs of Overheating
If the weather is extremely hot and humid or your body hasn't adapted yet, you may experience warning signs that your body is overheating, such as:
- Headache, which can be a sign of dehydration
- Increased effort needed to perform your typical physical activities, such as walking or jogging
- High heart rate after your body has already adapted to the heat
- Longer recovery time, which may include extreme fatigue
- Muscle cramps, which signal dehydration and low sodium
"These clues are telling your body to go easier," Dr. Sanders says. "Heat adds an extra layer of stress, and you may need to take a break from outdoor exercise. If the symptoms are severe or do not get better when you stop exercising, call your doctor."
5. Prioritize Recovery
The added strain on your body from heat and humidity may require a longer recovery time. But immediately following your workout, it's critical to cool down quickly.
"Try not to double up on your heat exposure," Dr. Sanders says. "Don't jump into a hot shower or sauna after working out in the heat. Sit with a wet towel on your neck or take a cool shower instead."
But a healthy recovery is also about what you do between workouts.
"You should be focusing on hydration, nutrition, stretching and sleep," Dr. Sanders says. "All those things will help you recover more quickly. Having those healthy practices in place helps to equip your body to handle heat better."
Next Steps and Useful Resources
- Want to discuss more with a doctor? Find a primary care provider or sports medicine doctor today.
