Beat the Heat: Prevention, Identification, and Management of Heat Illness

Summertime has finally arrived, bringing with it warmer weather and more fun in the sun. Whether you’re participating in family activities or organized sports leagues, many of us want to get outside and be more active. As we spend more time outdoors in the heat we need to be aware of the risk of heat illness. Heat illness can have serious and even deadly consequences, so it is important to be aware of how to prevent, identify and manage these illnesses. 

The body’s core temperature is normally 37 degrees Celsius and is maintained by balancing heat loss with heat gain. Heat illness occurs when the body is no longer able to get rid of the extra heat created during activity or from prolonged exposure to hot temperatures. Regulation of body temperature is controlled by the hypothalamus in the brain. We lose heat by sweating and dilating blood vessels and conserve heat through shivering and constricting blood vessels. Our ability to maintain our core temperature is affected by many environmental factors, including the temperature of the surrounding air and water, the air humidity, wind speed, clothing properties and skin moisture. Humidity increases the risk of heat illness because it makes it more difficult for sweat to evaporate and cool your body. Factors that increase the risk of heat illness include being dehydrated, consuming alcohol before or during activity, obesity, not being used to the climate and chronic illnesses. Older adults and young children are also at an increased risk. 


Heat Cramps

Heat cramps are painful muscle spasms that commonly occur during physical activity in a warm climate. Although they can occur in any muscle, they commonly occur in the calf muscles. 


It is safe to return to activity once the cramps resolve, but make sure to continue hydrating!

Heat Exhaustion

Heat exhaustion occurs when the body’s core temperature rises between 38.3-40 degrees celsius due to the heat regulatory mechanisms becoming overwhelmed. It is critical to recognize and manage heat exhaustion as early as possible because it can progress to heat stroke. As our thermoregulatory mechanisms become overwhelmed, we sweat. Sweating causes fluid loss and decreased blood volume. In heat, more blood flow is directed to the skin, arms and legs in an effort to try and increase heat loss. This results in less blood flow to the vital organs and can lead to shock. Heat exhaustion is commonly seen in athletes practicing or playing on a hot day. 

Signs and Symptoms


It is advised to wait at least 24 hours before returning to activity. It is not safe to return to activity the same day. 

Heat Stroke

Heat stroke is a medical emergency that can result in death if not treated promptly. It occurs when the body’s core temperature rises above 40 degrees Celsius and requires medical intervention.

Signs and Symptoms



There are a number of actions that can be taken to prevent heat illness. If you are planning on physical activity outdoors it is important to look at the forecast and plan appropriately. If the weather is supposed to be unusually warm or humid consider rescheduling your practice or activity, or moving indoors. If you can, schedule your event in the morning or evening rather than the hottest part of the day. If you are participating in a competition or event in a hot climate, make sure you acclimatize so your body is prepared (see Krystyna’s article for more information). Drink plenty of cool fluids or electrolytes, especially if you sweat a lot. Wearing loose clothing can help your body regulate temperature, and a hat can keep the hot sun off your head. Make sure to wear sunscreen as sunburned skin reduces the body’s ability to cool itself. If you are participating in physical activity in the heat, ensure you take frequent breaks in the shade. Heat illness can be a life threatening illness, but is easily preventable if appropriate precautions are taken. 

Crystal Bartkowski, B.A.,B.HPED.,CAT(C)
Certified Athletic Therapist

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