How long does heat exhaustion last? What to know about the heat-related illness.

Olivia Munson, USA TODAY

Updated June 19, 2024 at 12:59 AM·3 min read

When you're enjoying a bright, hot and sunny day, the last thing you want to think about is getting sick. We tend to think we can only get sick on cold days. But that's not true.

There are many illnesses that occur outside of the winter months and some are life-threatening. In fact, several of these conditions can be triggered by bright, sunny days.

Heat-related illnesses can range in severity and each should be taken seriously. Heat exhaustion can lead to further complications if not treated properly. Here is what you need to know about heat exhaustion, including its symptoms and how long it lasts.

What is heat exhaustion?

Heat exhaustion is one of several heat-related illnesses. According to the Center for Disease Control and Prevention, heat-related illnesses include:

Heat cramps
Heat rash
Heatstroke
Rhabdomyolysis
Heat syncope

All of these conditions can occur when your body overheats. This can be caused by exposure to hot temperatures, especially if it is humid or you are engaging in physical activity, according to the Mayo Clinic.

Your body's temperature is impacted by its environment. Your's body heat in relation to the environment's temperature is called "core temperature," according to the Mayo Clinic. The human body tends to remain at a core temperature of 98.6 degrees Fahrenheit.

Your body regulates temperature by sweating. When it is very hot outside, you are likely to sweat more since your body is trying to cool down. But if you are sweating excessively, this is not effective for maintaining homeostasis.

When you sweat, you lose fluids containing water, nutrients and salts that help you function properly. If you are not sufficiently replacing those lost fluids, you may experience a series of conditions, including dehydration or heat exhaustion.

Anyone can experience heat exhaustion. However, it can be impacted by other factors, such as age, alcohol use, medications or health conditions.

Older people and children are at higher risk of heat exhaustion since they are more likely to become dehydrated and often cannot regulate body temperature efficiently.

If you are drinking large quantities of alcohol, you also have a higher chance of heat exhaustion. When you are drinking, you can become dehydrated, which can lead to heat exhaustion. Alcohol also makes body temperature regulation harder, according to the Cleveland Clinic.

Some medications may trigger heat exhaustion if they lead to excessive loss of fluids, such as diuretics. Pre-existing conditions that lead to fluid loss, such as diabetes causing frequent urination, increase the risk of heat exhaustion.

Heat exhaustion symptoms

According to the Mayo Clinic and Cleveland Clinic, heat exhaustion symptoms include:

Dizziness, lightheadedness, feeling faint
Headache
Fever of 100 degrees Fahrenheit
Fatigue
Nausea
Muscle cramps
Excessive sweating
Cool, clammy skin with goosebumps
Swollen extremities (feet, hands, ankles)
Rapid heartbeat