What causes heat cramps?

Heat cramps can be caused by illness, activity, and heat. Specific causes include:

Heat cramps are caused by severe fluid and electrolyte loss, especially sodium.

Dehydration is defined as the significant loss of bodily fluids. Fluid is a component of blood, and it’s needed to transport nutrients throughout the body. Bodily fluid also helps to control body temperature.

Dehydration can be caused by:

What Are Heat Cramps?

It’s especially important to watch for dehydration symptoms in infants, babies, and small children. The following table lists symptoms of dehydration in adults and children.

Symptoms of dehydration in adultsSymptoms of dehydration in infants, babies, and children
thirstno wet diaper for 3 hours
dry mouth and tongueno tears while crying
headachesunken soft spot on the top of the head (fontanelle)
dark urinesunken eyes and cheeks

Whether it’s through exercise or labor, physical exertion can cause excessive sweating and fluid loss. Strenuous activity and copious sweating can lead to dehydration, electrolyte reduction, and heat cramps. This may be more likely to occur in hot temperatures, although it can also happen when it’s cold.

If you’re working or exercising outside during cold weather, you’re probably wearing layered clothing. Clothing can reduce the ability of sweat to evaporate and cool down skin. This can cause overheating, no matter what the temperature outside.

Being outside may also limit your access to water or other fluids, making it hard to rehydrate quickly and efficiently.

You don’t need to be out in the noonday sun to experience the ill effects of hot weather and high humidity.

Heat causes your internal temperature to rise. Your body attempts to cool itself down by sweating profusely and radiating heat out through the skin. If you don’t ingest more fluids and electrolytes than you’re losing, this natural cooling system will stop working efficiently.

You can become severely overheated and dehydrated outdoors or inside. The body’s internal temperature can rise to dangerous levels, even if you’re doing nothing more than sitting quietly in a very hot room with poor air circulation.

Children and adults over 60 are more susceptible to dehydration, heat cramps, and heat illness than people in other age groups. These conditions can also be more severe or dangerous when they occur in these populations.

Babies, children, and adolescents don’t adjust as quickly as adults to temperature changes and environmental heat. This makes them more vulnerable to heat cramps and heat stroke.

Children also sweat less and produce more body heat than adults do. If your child refuses to put on a coat when they’re outside, and you’re freezing despite wearing many layers, this is why. Their body is simply warmer than yours.

As people age, their bodies become less efficient at temperature regulation. This may be caused, at least in part, by the shrinkage of sweat glands. Sweat glands become diminished in size as part of the natural aging process. Less sweat equals less perspiration and a diminished ability to cool the body down.