Heat Stroke vs Heat Exhaustion: Understanding the Key Differences

When summer comes around, families look forward to spending more time outdoors. But the hot weather and summer heat can bring with them a risk of heat-related illnesses such as heat stroke and heat exhaustion, especially in a warm climate without taking precautions to ensure adequate hydration and sun protection. 

If you and your loved ones enjoy outdoor activities, especially during the warmer months, continue reading to learn the difference between heat exhaustion and heatstroke. We will discuss how to recognize these conditions, what to do if they occur, and how to prevent them. This information can be useful to everyone, but particularly to athletes, outdoor workers, and caretakers of young children who may need to distinguish between them to take timely and effective action.

What is a Heat-Related Illness?

A heat-related illness is an illness that occurs from exposure to high degrees of heat and humidity for prolonged durations, without breaks and enough water intake, affecting the body’s ability to cool itself. There are two main types of heat-related illnesses—heat stroke and heat exhaustion.

What is Heat Stroke?

Causes

Heat stroke, also called sunstroke, is a condition in which the body’s sweating mechanism does not work properly. This is called non-exertional heat stroke. Exertional heat stroke can occur despite the body’s heat regulation mechanisms working properly. 

In people with heat stroke, the core body temperature cannot be regulated and they are unable to stay cool. Hyperthermia (very high temperatures of 106 degrees Fahrenheit) can develop in under 15 minutes during a heat stroke—the normal temperature is 98.4F. 

Heat stroke is a life-threatening medical emergency. It can lead to permanent disability, even death, without immediate medical attention.

Risk Factors

Older adults and people with chronic medical conditions are at an increased risk of non-exertional heat stroke. Young, healthy individuals who perform strenuous exercise in warm, humid weather are at risk of exertional heat stroke.

Symptoms of Heat Stroke

The main warning signs and symptoms of heat stroke are hyperthermia (a very high body temperature), no sweating, flushed, hot, dry skin, a rapid, strong pulse, dizziness, nausea, throbbing headache, slurred speech, confusion, and seizures.

Read Next: Heat Stroke in Dogs: What to Look Out For.

What is Heat Exhaustion?

Causes

Heat exhaustion is a type of heat illness in which heavy sweating causes the body to lose large amounts of salt and water. 

Risk Factors

Risk factors for heat exhaustion include very young or older age, taking medications for high blood pressure, taking antipsychotics for mental health conditions, and working in extreme heat environments. Outdoor workers are at an increased risk of heat exhaustion, especially during heat waves.

Symptoms and Signs of Heat Exhaustion

Symptoms of heat exhaustion include increased body temperature, heavy sweating, pale, clammy skin, dizziness, weakness, headache, nausea, vomiting, and irritability. Other symptoms can include increased thirst and decreased urine output. 

Heat-Related Illnesses in Infants and Children

Infants and children are at a higher risk of heat-related illnesses due to certain factors such as a higher metabolism, decreased sweating, less effective kidney function, and increased risk of sunburn. Signs of heat-related illnesses in infants may include sleepiness or lethargy; hot, flushed skin or pale, clammy skin; decreased urination; and body temperature above 102F (use a rectal thermometer to measure a baby’s body temperature accurately).

Key Differences Between Heat Stroke and Heat Exhaustion

How Do You Tell If You Have Heat Stroke or Heat Exhaustion?

A key way to tell if you have heat stroke or heat exhaustion is that in heat stroke sweating is absent while in heat exhaustion there is heavy sweating. In addition, core body temperature is usually above 104F in heat stroke and below 104F in heat exhaustion.

Which Is Worse: Heat Stroke or Heat Exhaustion? 

Heat stroke is a more serious heat-related illness than heat exhaustion. The core temperature in heat stroke patients can be very high. Left untreated, heat stroke can be fatal.

First-Aid Measures and Treatments for a Heat-Related Illness

What To Do If Someone Has Heat Stroke?

If someone has signs and symptoms of heat stroke, they need emergency treatment. Call 911 or emergency services. While you wait for EMS, move the person to a shady or cool area and stay with them until help arrives. Remove unnecessary clothing for immediate cooling. Try to cool their body with an ice-cold bath (if possible). Otherwise, try wetting the skin with cold compresses or ice packs, placing cold, wet cloths on the skin, or soaking their clothing in water.

How Do You Treat Heat Exhaustion at Home?

To treat heat exhaustion at home, take the person to a cooler place. Remove unnecessary outer clothing such as jackets, long-sleeved tops, shoes, and socks. Give them cold liquids to drink, such as frequent sips of cold water. Apply cold compresses and/or wash their face and neck with cold water. High blood pressure can be treated with certain medications if one has been prescribed for the person.

Note: Mild heat exhaustion can be treated at home. But if someone is experiencing heat exhaustion symptoms that appear to be severe, take them to a medical clinic or emergency room or call 911. Even if they don’t lose consciousness, stay with them until EMS arrives. 

When To Go To The ER For Heat Exhaustion and Heat Stroke?

Go to the ER as soon as possible for a heat illness if you suspect heat stroke. This is a medical emergency and requires immediate medical treatment. Serious signs and symptoms that warrant emergency medical care include a very high body temperature, confusion, agitation, seizures, or loss of consciousness.

How Long Can Heat Exhaustion Last?

Recovery from heat exhaustion usually takes 24-48 hours. However, the recovery timeline depends on the severity of the heat illness. You may need to be hospitalized to manage fluid and electrolytes. A heat illness can also worsen other medical conditions that may need to be managed in the hospital.

Prevention: How To Stay Safe In Hot Weather?

• Stay hydrated. Drink plenty of fluids, especially during strenuous outdoor activities in hot weather. A sports drink or water is preferable. Make sure you have enough cool water to last you throughout the day. Avoid caffeine, colas, teas, coffees, and alcohol, as they can contribute to dehydration.

• Dress in breathable, loose-fitting, light-colored, and lightweight clothing.

• Mist or wet yourself with a spray bottle periodically to prevent overheating. 

• Plan outdoor activities in the early morning or late evening when it is cooler.

• Pay attention to heat advisories and stay indoors on particularly hot days.

• Make sure you get enough rest in shaded or cool areas during outdoor activities.

• Protect yourself from the sun with a wide-brimmed hat, sunglasses, umbrella, and SPF 15 or higher sunscreen.

• Get your body acclimatized to the heat by slowly increasing the amount of time you spend outdoors.

• Avoid sudden temperature changes, such as going from air conditioning to an outdoor area with a high heat index.

Other Types of Heat Illnesses

Rhabdomyolysis

Rhabdomyolysis is a serious condition that occurs due to strenuous activity and heat stress in hot and humid weather. It results in a rapid breakdown of muscle cells, leading to muscle death. Muscle breakdown causes the release of large quantities of myoglobin and potassium into the bloodstream, causing kidney damage and heart rhythm problems. 

Early warning signs of rhabdomyolysis include muscle cramps, weakness, inability to exercise, and dark-colored urine (tea or cola-colored).

If you suspect rhabdomyolysis, stop exercising, drink lots of fluids, preferably water, and get immediate medical care at the nearest health clinic or emergency room. Doctors may order a creatine kinase blood test to diagnose rhabdomyolysis.

Heat Cramps

Heat cramps affect people who sweat a lot during physical activity. As a result of the sweating, the body loses salt and water. This causes painful muscle cramps called heat cramps, which can also be a symptom of heat exhaustion. 

Treatment for heat cramps consists of the following: 

• Avoid exposure to more heat. 

• Drink water or a sports drink to replace electrolytes. 

• Eat a snack containing carbohydrates. 

• Do not take salt tablets. 

• Get medical help if the cramps continue for more than an hour. 

• Go to a medical clinic if you have heart problems or are on a low-sodium diet. 

Heat Syncope

Heat syncope is a dizziness or fainting episode that occurs after standing for too long in a hot environment or after standing up from a sitting or lying position. Lack of proper heat acclimatization and dehydration can trigger heat syncope. 

If it happens, you should sit down or lie down in a cool place and take small sips of cold water, sports drinks, or clear juices.

Heat Rash

Excessive sweating in hot weather with high humidity levels can lead to a skin irritation called heat rash. It appears as small clusters of red bumps or pimples in sweat-prone areas with moist skin, such as the neck, chest, elbow creases, and groin. Treatment for heat rash consists of keeping the area as dry as possible and using powder to soak up the sweat.