Heat-related illness in young athletes

Girl drinking water after exercising Girl drinking water after exercising  

Sports are an important part of summer for many children and teens. But physical activity in heat and humidity can increase the risk of the heat-related illness.

The American Academy of Pediatrics lists a number of factors that make children and teens more vulnerable to heat-related illness caused by physical exertion. They include:

  • a hot or humid climate
  • insufficient adjustment to exercising in the heat and humidity
  • insufficient adjustment to the intensity or duration of activity or to the uniform and protective equipment
  • excessive physical exertion in terms of intensity or duration
  • clothing, uniform or protective equipment that does not allow the body to release enough heat
  • poor hydration
  • insufficient cardiovascular fitness
  • inadequate sleep or rest
  • insufficient rest and recovery time between same-day practice or training sessions and competitions
  • being overweight or obese
  • a current or recent illness and other medical conditions (or medications) that affect hydration and the body’s ability to regulate temperature.

Common heat-related illnesses during sports activities

Dehydration is commonly the first sign of a heat-related illness​. If it is not addressed correctly, it can be followed by:

  • heat cramps
  • hyponatremia
  • heat exhaustion
  • in extreme cases, heat stroke – a medical emergency.

Heat cramps

Heat cramps are the most common heat-related injury. They usually occur in cases of mild dehydration or salt loss, normally after someone has been physically active for a while.

Symptoms of heat cramps include intense muscle pain or spasms that are not caused by injury. These cramps normally affect the legs, but they can also affect the arms or abdomen.

How to treat heat cramps

If your child has heat cramps, they should:

  • stop exercising and sit down
  • drink clear juice or a sports drink to help replace fluid and salt
  • do some light stretching or relaxation.

Massaging the area of the body affected by the cramps may also help.

Your child can return to the physical activity when the cramps go away.

When to see a doctor

Take your child to a doctor if the cramps do not go away after an hour.


The body needs a tiny amount of sodium to control blood pressure and blood volume and help muscles and nerves work properly.

Hyponatremia occurs when the body’s blood sodium level becomes too low. It is more likely to happen if a child:

  • does not usually get enough salt in their diet
  • loses large amounts of salt during strenuous or prolonged exercise
  • drinks much more water than they need during or after exercise.

Hyponatremia is quite a rare condition, but it can be dangerous. Teens are at higher risk of hyponatremia than younger children.

How to treat hyponatremia

For prolonged activity (one hour or more) in the sun, your child should replace lost water and lost salt with a sports drink or a meal. Salt pills are not recommended.

Heat exhaustion

Heat exhaustion is caused by loss of water and salt, often as a result of exercise in hot weather. If heat exhaustion is not treated, it may progress to heat stroke.

Symptoms of heat exhaustion include:

  • normal or raised body temperature, but less than 40°C (104°F)
  • pale skin
  • cool and moist skin
  • headache
  • nausea or vomiting
  • dizziness, weakness or fainting.

How to treat heat exhaustion

  • Move your child to a shady or air-conditioned area and have them lie comfortably.
  • Remove extra clothing and sports equipment, if any.
  • Cool them with cold water, fans or cold towels.
  • If your child is not vomiting or feeling nauseous, have them drink chilled water, juice or a sports drink.

When to see a doctor

Take your child to see a doctor if:

  • they do not seem better after an hour
  • their symptoms are severe
  • they seem confused or disoriented
  • they are behaving oddly.

Heat stroke

Heat stroke is a dangerous illness that can lead to organ damage or death. In fact, heat stroke caused by exertion is the leading cause of preventable death in youth sports.

Heat stroke happens when a child's body creates more heat than it can release. The main symptoms are:

  • increase in core body temperature, usually above 40° C (104° F)
  • break down of the central nervous system, which may appear as altered consciousness, seizures, confusion, emotional instability or irrational behaviour
  • hot and wet or dry skin (profuse sweating usually occurs with intense exertion).

How to treat heat stroke

  • Heat stroke is a medical emergency. Call 911 right away.
  • While waiting for emergency services, remove the child's clothing and any sports equipment.
  • Begin cooling the child by any means available, including immersing them in cold water, spraying them with cold water, placing fans in front of them or using ice bags.
  • Do not give the child anything to drink.
  • Monitor the child's body temperature.

Even if a child with heat stroke feels better after cooling, they should not return to their activities until they have been seen by a doctor.

How to prevent heat-related illness during sports and exercise

  • Make sure your child’s coach or supervisor knows about exercising in the heat and has a plan to deal with heat-related illnesses if they arise.
  • Reduce the intensity of exercise when it is very hot, humid or sunny.
  • Take frequent breaks.
  • Wear lightweight, light-coloured, loose clothing.
  • Make sure your child is well hydrated before exercising.
  • Make sure your child drinks every 15 to 20 minutes when exercising, even if they do not feel thirsty. Generally, nine to 12 year olds need 100 mL to 250 mL every 20 minutes. Teens need up to 1 L to 1.5 L of fluid for every hour of exercise.
  • If your child has been exercising for less than an hour, they can rehydrate with water. If they have been exercising for more than an hour, they should have a sports drink to replace the water and salt lost through sweat. Do not use salt tablets to restore the levels of sodium and other electrolytes in the blood, as they provide too much salt.
  • If it is very hot and humid, cancel the activity or move to an air-conditioned space.

Key points

  • A number of factors make heat-related illness more likely for young athletes. These include wearing clothing or protective equipment that does not allow enough heat to escape from the body, exercising too intensively or for too long in the heat and not having enough rest between same-day training sessions and competitions.
  • Dehydration is a common heat-related illness. If it is not treated in time or correctly, it can result in heat cramps, hyponatremia, heat exhaustion and heat stroke.
  • Hyponatremia, heat cramps and heat exhaustion can usually be treated first by replacing lost fluids and salt, resting in a shaded area and removing extra clothing or equipment, if any. A child should see a doctor only if their symptoms last more than an hour or get worse.
  • Heat stroke is a medical emergency. While waiting for a doctor, it is important to cool the child using whatever means are available, such as immersing them in or spraying them with cold water.
  • To prevent the risk of heat-related illness during physical activity, drink enough fluids before, during and after exercise, take frequent breaks, reduce the intensity and length of the exercise and wear lightweight and loose clothing.
​Shawna Silver, MD, FRCPC, FAAP, PEng


American Academy of Pediatrics Committee on Sports Medicine and Fitness. Climatic heat stress and the exercising child or adolescent. Pediatrics. 2011;128(3):741-747

Bergeron, MF (2013). Reducing Sports Heat Illness Risk. Pediatrics in Review. 2013; 34:270-279.

Centers for Disease Control and Prevention. Tips for Preventing Heat-Related IllnessWashington, DC: Department of Health and Human Services. 

National Athletic Trainers' Association. Parents' and Coaches' Guide to Dehydration and Other Heat Illnesses in Children. Dallas: National Athletic Trainers' Association; 2003.​