July 14, 2020/Exercise & Fitness

Should You Exercise When It’s Hot?

Anyone can get heat illness, so watch for signs that you need to cool down

woman exercising in summer heat

Warm, sunny days are perfect for outdoor exercise. You don’t need a jacket or gloves. You don’t have to worry about slipping on a patch of ice during your morning jog. Just throw on your shoes and go, right?


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

Careful — sunny days have risks, too. If your body gets too hot, you could get heat illness. In mild cases, you might feel miserable for a few hours. But serious cases can be life-threatening.

Emergency room physician Tom Waters, MD, explains the different types of heat illness, their symptoms and how you can prevent them.

What is heat illness?

When we’re hot, our bodies sweat to cool us down. But sweating can only do so much. Heat illness happens when your body’s cooling efforts can’t keep up with the temperature and humidity around you.

“Sweating is our main mechanism to dissipate heat. When it’s hot and humid, we’re not very efficient at getting rid of heat,” Dr. Waters explains.

That’s when a heat illness can happen. Your body temperature rises, and you need to take quick action to lower it. Just getting out of the sun and drinking fluids might be enough to make you feel better. But if your symptoms are more severe, go to the emergency room.

Young children and older adults are more susceptible to high heat. They should take frequent breaks from the heat and drink plenty of fluids.

Heat cramps

Cramps are the first sign you’re overdoing it in the heat and need to cool down.

If you feel muscle spasms during your workout:

  • Stop and get to a cooler area.
  • Gently stretch and massage the affected muscles.
  • Drink water or an electrolyte drink.
  • Avoid drinks that contain caffeine or alcohol.

Don’t exercise again for the rest of the day, and make sure you’ve had plenty to drink. If your cramps don’t go away after an hour or you have heart problems, get medical help right away.

Heat exhaustion

Heat exhaustion is more severe than heat cramps. You may have symptoms, such as:

  • Extreme fatigue.
  • Shortness of breath.
  • Dizziness.
  • Vomiting.
  • Fainting.
  • Skin that feels cold and clammy or hot and dry.
  • Low blood pressure.
  • Weak but rapid pulse.
  • Feeling chilled or getting goosebumps even though it’s hot.

To treat heat exhaustion, get out of the heat and sun ASAP. If possible, go inside an air-conditioned building. Loosen your clothes and drink water or electrolyte drinks. If you have access to a cool bath or wet washcloths, use one or both to get your skin’s temperature down.

If you’re vomiting or symptoms don’t get better within a few minutes, call 911 or head to the emergency room, Dr. Waters says.


Heatstroke is the most severe form of heat illness. This life-threatening condition needs immediate medical attention. If you don’t get treatment, it can lead to brain damage or death.

Symptoms can include:

  • Temperature of 103 degrees or higher.
  • Skin that is hot, red or dry.
  • Feeling disoriented or confused.
  • Dizziness.
  • Rapid pulse and breathing.
  • Fainting.


If you think a person has heatstroke, seek emergency medical care. Get them to a cooler place while you wait for an ambulance. If you’re driving them to an emergency room, use cold compresses and air conditioning to cool them down in the vehicle.

“If you notice a loved one is not acting right — if they’re confused or not themselves — they may be developing heatstroke. Get them out of the heat,” says Dr. Waters. “If they don’t recover quickly after that, or if they continue to act confused, take them to the emergency room right away.”

Working out in warmer months

You don’t have to avoid outdoor workouts when it’s warm. Here’s what you can do to prevent heat illness:

  • Fluids are your friend. Drink water or electrolyte drinks every 15 minutes when exercising in the heat, even if you’re not thirsty. Aim for 2 to 4 cups (16 to 32 ounces) of fluids each hour. Start drinking before your workout, keep drinking as you go and continue to drink afterward.
  • Chill out about your workout. Don’t duplicate your indoor routine when it’s muggy and in the 80s. Hot temperatures put stress on the body as it works harder to cool you down. If you want to exercise outside, take it down a few notches in intensity. You may also need to make it shorter than usual. A less intense, shorter workout is not a sign that you’re out of shape. It’s a smart way to stay healthy.
  • Try something different. That 10-mile run isn’t the best idea when it’s hot out. A bike ride gives you a breeze and makes you feel cooler. Or enjoy a swim when the mercury climbs.
  • Go in the morning or evening. The middle of the day isn’t a good time to exercise in the warmer months. Go out before 9 a.m. or after 7 p.m. to avoid the hot sun and excessive heat. If the temperature is 80 degrees or higher and the humidity is above 80%, take your workout inside.

Heatstroke is no joke

The symptoms of heat exhaustion and heatstroke can be difficult to tell apart. If you’re not sure, don’t try to guess or wait. The safest bet is to head to the emergency room.


Learn more about our editorial process.

Related Articles

Lifeguard looking at water with binoculars while two kids fly kites on the beach
May 23, 2024/Primary Care
12 Summer Health Risks To Watch Out For

From bug bites and blisters to sunstroke and swimming safety, here’s how to stay well this season

person running with food and fitness images floating behind
March 6, 2024/Exercise & Fitness
Is It Safe to Work Out While You’re Fasting?

It’s best to exercise before or after your fast, instead of during it

Person overheated lying on chair on the beach; heart rythym next to him
December 4, 2023/Heart Health
How the Heat Can Affect Your Heart

Sizzling temperatures force your heart to work much harder

A person sits on a park bench with their head in their hands while another person gives them water.
June 20, 2023/Primary Care
Heat Exhaustion and Heat Stroke Are Too Hot To Handle on Your Own

Both heat illnesses can be life-threatening if left untreated

Hand holding cellphone with walking app, with feet walking and footprints
May 17, 2024/Exercise & Fitness
Should You Aim To Walk 10,000 Steps a Day?

Walking is a great goal, but how many steps are best for you depends on factors like your fitness level and age

Person walking on walking pad at home office desk
May 16, 2024/Exercise & Fitness
What’s a Walking Pad — And Do They Really Work?

A walking pad is a simplified treadmill that can fit under your desk and help you get more movement in your day

Person stretching on floor mats in their home gym area
May 8, 2024/Exercise & Fitness
Strength Finder: How To Create a Home Gym You’ll Use

First, reflect on your specific workout goals, and then pick and choose your fitness equipment

Person jogging in foggy park among big, green trees
May 2, 2024/Exercise & Fitness
What Is Slow Running and Does It Work?

Reducing your pace allows you to log more miles and train your body for the stress of running

Trending Topics

Person in yellow tshirt and blue jeans relaxing on green couch in living room reading texts on their phone.
Here’s How Many Calories You Naturally Burn in a Day

Your metabolism may torch 1,300 to 2,000 calories daily with no activity

woman snacking on raisins and nuts
52 Foods High In Iron

Pump up your iron intake with foods like tuna, tofu and turkey