Subscribe to Our
Sports Medicine Blog

Sports Medicine Facebook

Heat illness

Hot, muggy, summer days are great for spending the day in a pool, but not so great for athletic activities. As the temperature and humidity rise, attention needs to be given to heat-related injuries. When the body is unable to cool itself by sweating, heat illness can occur.

Factors that can lead to heat illness are:

  • High temperature
  • High humidity
  • Direct sun or heat
  • Limited air movement
  • Physical exertion
  • Poor physical conditioning
  • Certain medications, and/or
  • Inadequate tolerance for hot environments.

Populations most at risk for heat illness include:

  • Infants and young children,
  • Adults age 65 and over,
  • Mental illness, and/or
  • Physical illness (i.e., such as heart disease or high blood pressure)

Heat illness can be broken down into three categories

Heat cramps

Heat cramps are painful, involuntary muscle spasms that usually occur during heavy exercise in hot environments. This type of muscle cramp is often due to inadequate fluid intake or an imbalance between water and electrolytes.

Signs and symptoms:

  • Profuse sweating
  • Muscle cramps: most often occurring in calves, arms, abdominals, or back


  • Fluid replacement: water, clear juice or sports drinks
  • Gentle stretching and massage of the affected muscle group
  • Ice application
  • Activities for the rest of the day should stop; likelihood of cramps returning are great


  • Diet rich in potassium and calcium
  • Replacement of fluids after workouts that include a solution of electrolytes (potassium, sodium, and calcium); carbohydrates may be helpful
  • Do not wait until you're thirsty before drinking water; schedule water breaks at regular intervals throughout the exercise session to help maintain hydration levels in the body

Heat exhaustion

Heat exhaustion results from dehydration. Signs and symptoms – which can resemble shock – often, begin suddenly, sometimes after excessive exercise, heavy perspiration and inadequate fluid intake.

Signs and symptoms:

  • Flushed skin, profuse sweating
  • Weakness and moist skin
  • Mildly elevated body temperature
  • Dizziness, headache
  • Lightheadedness or fainting
  • Upset stomach, vomiting
  • Mood changes that may include irritability or confusion
  • Dark colored urine
  • Rapid pulse and breathing rate


  • Remove athlete from sun/hot environment; place in cool or air conditioned place
  • Replace fluids
  • Remove excess clothing
  • Place cool compress directly on body
  • Lay person down, elevate legs and feet slightly
  • Monitor person closely. Heat exhaustion can quickly become heatstroke!


  • Consistent replacement of fluids before, during and after practice
  • Balanced diet
  • Wearing light-colored, loose-fitting, moisture-wicking clothes
  • Avoid drinks that contain caffeine, large amounts of sugar, or alcohol as they cause additional fluid loss


Heatstroke is the most severe heat-related illness. Heatstroke can be a fatal condition resulting in the body's inability to regulate body temperature through the act of sweating. The main sign of heatstroke is a noticeably elevated body temperature (i.e., generally greater than 104 F) with changes in mental status ranging from personality to confusion and coma. This condition is a medical emergency.

Signs and symptoms:

  • Headache, dizziness
  • Unconsciousness
  • Red, hot, dry skin with no sweating
  • Mental confusion
  • Rapid pulse rate
  • Loss of consciousness
  • Seizure/convulsions
  • Very high body temperature


  • Cool individual as rapidly as possible, place cool compresses directly on skin
  • Move to cool, well ventilated location
  • Remove as much clothing as possible
  • Monitor vital signs
  • Activate Emergency Medical Service (EMS)

The goal of treatment for these heat-related injuries is to decrease body temperature and replace fluids. It's important to monitor body temperature, heart rate and respiration rate. If any changes occur, or there is any doubt to the severity of the heat illness, contact an Emergency Medical Service (call 911).

Prevention is the best defense against heat illness. On hot and humid days, workouts should be scheduled for the early morning or evening hours. Wearing light-colored, loose-fitting clothing, hat, sunglasses, and the use of sunscreen is advised. During physical activity, it's recommended that participants consume one cup of water every 15-20 minutes; avoid very cold drinks – they can often cause stomach cramps. Additionally, skipping drinks that contain caffeine, high sugar content, or alcohol is key to proper hydration.

Finally, familiarity with the Heat Index (i.e., the temperature the body feels when heat and humidity are combined) is an important step for avoiding potentially dangerous or deadly exposures to hot environments. As a general guide, use the following temperature and humidity levels to identify potential heat problems:

  • 80 - 90 F, with 70-90 percent relative humidity – Fatigue possible when combined with prolonged exposure and physical activity
  • 90 - 105 F, with 50-90 percent humidity – Sunstroke, heat cramps, and heat exhaustion possible
  • 105 - 130 F, with 40 percent or more humidity – Sunstroke, heat cramps and heat exhaustion likely; heatstroke possible
  • 130 F or greater, 40 percent or more humidity – Heat stroke likely with continued exposure

Heat injuries can be extremely serious, even leading to death. For additional questions on heat-related illnesses, other sports medicine topics or to schedule a Free Injury Evaluation, call the Aurora Sports Medicine Hotline™ at 414-219-7776 or 800-219-7776.