After a long winter, the heat of summer can be a shock to the system. And summers in the Upper Midwest can get hot – really, really hot. In fact, the summer of 2021 became the hottest season ever recorded in the U.S., with temperatures consistently 2-4 degrees higher than average. While that may not seem like a lot, 2-4 degrees can be the difference between enjoying a warm summer day and experiencing a heat-related illness.

Whether you’re relaxing on the beach, riding your bike or mowing the lawn, or trying to sleep without air conditioning the heat can get to you. That’s why it’s important to know the symptoms of both heat exhaustion and heat stroke, so you can recognize right away when it’s time to cool off. Read on for signs of heat exhaustion and heat stroke and tips on how to stay cool.

What is happening in your body when it’s hot outside?

Your body is extremely sensitive to its internal temperature. Changes of just one or two degrees can result in several physical functions not working as well as they should. Our brain wants to keep the body at or around 98.6 degrees Fahrenheit, so when we are exposed to extreme heat, two things happen:

  • We sweat to cool down, because the process of sweat evaporating off our skin has a cooling effect.
  • We pump blood to the skin’s surface and into our extremities to allow all the internal heat carried by our blood to escape. This is why we often appear flushed when it’s hot outside.

These physical responses are hard on the body and can lead to heat-related illness.

What are the types of heat-related illness?

There are three main types of heat-related illnesses: heat cramps, heat exhaustion and heat stroke. While the three conditions are related, the difference between each is their severity.

Heat cramps

Heat cramps are a mild form of heat-related illness. After sweating in the heat for a long time, your body can run out of the water and other fluids it needs to function at its best. This leads to dehydration, a condition which causes painful stomach cramps and muscle spasms in your back and arms as your body attempts to make do without the essential electrolytes it would get from fluids.

Heat exhaustion

Heat exhaustion is a less severe condition than heat stroke. It often comes before heat stroke, but not always. Heat exhaustion happens when your body becomes fatigued from trying to cool itself down for extended periods of time. Two of the biggest contributing factors to heat exhaustion, aside from high temperatures, are high humidity and physical activity.

Heat stroke

After enough time in very hot conditions, your body is unable to maintain its physical responses to heat. When these physical responses fail, it leads to heat stroke. During heat stroke, your internal temperature rises to 103 degrees Fahrenheit and higher in just a few minutes. Heat stroke is life-threatening and requires immediate emergency medical attention.

Who is most at risk of heat-related illness?

Certain factors make it harder for your body to regulate its temperature, like age, weight, exercise and certain chronic conditions. The following groups are the most vulnerable when it comes to heat exhaustion and heat stroke:

Alcohol consumption, which causes dehydration under any conditions, can also put you at a higher risk of heat exhaustion.

What are the symptoms of heat exhaustion?

Trying to keep cool in very hot weather puts a massive strain on the body. It doesn’t take long for us to run out of physical energy and resources. When this happens, we become vulnerable to dehydration, heat cramps, heat exhaustion and eventually heat stroke.

The symptoms of heat exhaustion include:

  • Muscle cramps
  • Headache
  • Nausea
  • Fatigue
  • Dizziness or confusion
  • Excessive sweating with cold, clammy skin

The good news is that people can recover from heat exhaustion quickly with the right treatment.

How do you treat heat exhaustion?

Heat exhaustion can often be treated on your own, without medical intervention. However, it should still be taken very seriously. If you’re experiencing any of the symptoms of heat exhaustion we listed above, take the following steps right away:

  • Find a spot in the shade or head indoors, ideally somewhere with air conditioning.
  • Lie down with your legs elevated above your head.
  • Take a cool shower or immerse yourself in a cool bath. If these are unavailable, wet cloths with cool water and place them on your skin.
  • Drink small sips of room temperature or cool water, which is easier for your body to process than cold water.
  • Consume sports drinks infused with electrolytes, and foods such as bananas, cucumbers, watermelon and salty snacks like pretzels and crackers.
  • Wait 24-48 hours before resuming any physical activity.

If you’re worried about someone who may not have access to an indoor space, or is confused, weak or throwing up in the heat, call 911.

What are the symptoms of heat stroke?

Heat stroke, also called sun stroke, occurs when your body can no longer sustain its physical responses to heat. Without its usual cooling methods, your body loses control of its internal temperature, which can shoot up to 103 degrees Fahrenheit in minutes. This causes the serious malfunction of several organ systems in your body, including your brain. Symptoms of heat stroke include:

  • Hot, dry skin with an absence of sweating
  • Fast, shallow breathing
  • Rapid heart rate
  • Confusion, irritability or slurred speech
  • Poor balance
  • Lightheadedness or fainting
  • Loss of consciousness
  • Seizures (in severe cases)

How do you treat heat stroke?

Heat stroke is a medical emergency because it can cause permanent damage to the body. If you notice someone displaying symptoms of heat stroke, call 911 right away.

While you wait for help to arrive, take immediate steps to cool the person down:

  • Move them to a cool, well-ventilated place
  • Loosen tight clothing, remove heavy clothing and take off any layers
  • Apply ice packs or cold compresses to their neck, armpits and groin
  • Immerse them in cool water in the bathtub or shower, or mist their body with water and blow air across it
  • If they are still conscious, encourage them to drink room temperature or cool water or a sports drink

How soon do heat stroke symptoms appear?

Heat stroke can set in quickly over the course of 10-15 minutes, or slowly, developing over several hours or days. It’s important to monitor someone for signs of heat exhaustion or heat stroke for a few days after extreme heat exposure.

It’s also possible to experience the sudden onset of heat stroke without any preceding heat exhaustion.

What is exertional heat stroke?

Exertional heat stroke is heat stroke caused by strenuous exercise in hot conditions. Athletes and sport coaches holding practice, meets or matches outdoors in the summertime should be very aware of the symptoms of heat stroke.

But it doesn’t just happen to athletes. Anyone who is active in the heat, including outdoor laborers, safety personnel and factory workers, can get exertional heat stroke. Even doing yard work at home carries some risk of heat exhaustion and heat stroke.

Fatigue and muscle cramps are some of the first signals that your body is overheating, and should be your cue to head indoors or into the shade to rest.

How to exercise safely in the heat

There’s nothing like being active in beautiful summer weather. However, just like exercising in the cold, there are a few things to think about before exercising in the heat. Here’s a few tips on how to do it safely:

  • Drink 5-10 ounces of water every 15-20 minutes during a workout
  • Wear light-colored clothing made from cotton or a sweat-wicking material
  • Schedule any physical activities for the early morning or evening
  • Workout at an indoor gym or at home
  • Try aquatic exercise

If you choose to exercise outside, take it easy at first and increase intensity slowly over the course of one or several workouts. This gives your body time to adjust to exertion in hotter conditions.

A male construction worker removes his hard hat to wipe the sweat from his brow.

How to prevent heat exhaustion and heat stroke

On very hot, humid days, try to stay in an air-conditioned space and cancel outdoor events, if possible. If that’s not an option, here are some tips for preventing heat stroke and heat exhaustion:

  • Drink plenty of water. Thirst is one of the first signs that you’re becoming dehydrated, so don’t wait until you’re thirsty to drink water. Staying hydrated is important year-round, but especially on hot summer days. Overall, you should aim for at least 6-8 glasses of water every day – or more when you exercise.
  • Avoid strenuous activity. While it may be possible to do lighter forms of exercise, like walking or cycling, if you’re taking steps to do them safely, avoid doing anything that puts a large amount of strain on your body – such as heavy weightlifting.
  • Apply sunscreen and stay in the shade. Reapply sunscreen every two hours, especially if you’re swimming or sweating, even when you’re in the shade. You should also opt for wide-brimmed hats, sunglasses with UV protection and other protective clothing on sunny days. Try to stay in shaded areas when the sun is at its strongest – usually between 10 a.m. and 4 p.m.
  • Wear appropriate clothing. Choose clothing that is made of thinner, lighter materials, like linen or cotton, to help your body stay cool. If you know you’ll be spending time in the sun without access to shade, make sure to wear a wide-brimmed hat and UV protective clothing that covers your arms and legs.
  • Cool off at night. Cooler nighttime temperatures give your body a chance to recover, but sometimes the day’s heat carries over into the night. Without air- conditioning, it can be hard to sleep when it’s too hot. Before going to bed, take a cool shower, put a sheet in the freezer or set up fans around your bedroom to make sure you stay cool through the night and can be ready to take on another hot day.
  • Know the signs and symptoms. Being aware of the symptoms of heat exhaustion and heat stroke can help you and others stay safe.

Practice summer safety

Summer is a season full of fun and possibility. While it’s easy to get swept up in all our favorite outdoor activities after a long winter, taking a few moments to prepare can make the difference between a great day and a dangerous situation.

If you’re feeling sick after spending time in the heat, our urgent care services are here to help you feel better and get you back out there.