Heat-related illnesses increase when the air temperature and humidity are high and the sun is bright. A fitness professional should be able to differentiate between cramps, syncope (fainting), exhaustion and stroke.
A mild form of heat illness characterized by collapse or fainting. It occurs when blood vessels dilate or blood pools
in the legs or arms.
• rapid fatigue
• standing in the heat
• not acclimated to heat
• lay the person down in a cool area
• replace fluids
Another mild form of heat illness
• painful muscle cramps usually in arms, legs, or abdomen
• prolonged sweating = loss of water and electrolytes (sodium, chloride, potassium, magnesium, and calcium)
• not acclimated to heat
• increase water and electrolyte intake, especially sodium
• approximation of muscle. If that does not work, use direct compression of muscle. If approximation and
compression do not work, use reciprocal inhibition innervation (isometrically contract the opposite muscle
• ice massage — do not manually massage the area
• rest in cool area. Often unable to return to activity the same day, as heat cramps are likely to reoccur
A moderate form of heat illness due to environmental heat and exercise; categorized as mild hyperthermia. Most
signs of heat exhaustion can be recognized and acted upon before the condition becomes more serious.
• dry tongue and mouth
• profuse sweating
• mental dullness
• loss of coordination
• stomach and/or muscle cramps
• nausea or vomiting
• pale skin
• rectal (core) temperature less than 104 degrees. Rectal temperature is the most effective method for differentiating between heat exhaustion and heat stroke.
• rapid pulse
• small amount of urine produced
• not drinking enough water/fluid
• prolonged sweating
• poor physical conditioning
• replace fluids
• administer intravenous fluids
• place person in a cool environment
• apply sponge with cool water, especially to the head and neck
• take rectal temperature
A severe form of heat illness. This is a serious life-threatening emergency that may lead to brain damage or death.
Many signs of impending heat stroke present prior to the actual occurrence of heat stroke.
• cessation of sweating (occurs in roughly 25% of heat stroke cases)
• confusion or irrational behavior
• sudden collapse with loss of consciousness
• flushed hot skin
• rapid, strong pulse (160-180 bpm)
• rectal temperature of 104 degrees or higher (107 degrees = death)
• increased/shallow respirations
• typically blood pressure doesn’t change
Unknown; but the condition is defined as a breakdown of the thermoregulatory mechanism caused by an
excessively high core temperature
• must decrease body temperature within 45 minutes
• get to an emergency room
• place in a cool location
• immerse in an ice bath, or sponge with ice water and fan; keep an inflatable kids pool on sidelines. Decreasing
body temperature is more important than water replacement.
Preventing Heat Illness
Fluids should be easily accessible before, during and after activity. Drink 7-10 ounces of cold water and/or a 6% glucose sports drink every 15 minutes to match sweat loss. A 2% loss of body weight impairs cardiorespiratory and thermoregulatory systems and is categorized as mild dehydration. Too much water decreases sodium levels which compromises the central nervous system and can cause hyponatremia.
Progress training to acclimate to hot weather and used to exercise. A person can expect to achieve 80% acclimatization in 5-6 days, with 2 hours of activity in the morning and 2 hours in the afternoon. 100% acclimatization will take 10-14 days. Most heat-related illnesses occur during the first few days of training. Fitness professionals must take routine temperature and humidity readings, and provide adequate rest periods in a cool, shaded area.
Identifying Susceptible Individuals
People typically more susceptible to heat illness include:
• those with greater muscle mass
• overweight individuals
• those with poor fitness levels
• excessive sweaters
• people that don’t dissipate heat well (including carriers of Sickle Cell Anemia)
• those with a history of heat illness
• those with a poor diet
• people with an infection, fever, gastrointestinal condition, or diarrhea
• those on certain medications
Keep Weight Records
Weigh before and after activity for the first two weeks. A loss of 3% – 5% of your body weight is very dangerous because blood volume is decreased. A well-balanced diet is a must.
Begin with lightweight and light-colored uniforms. Loose fitting T-shirts and shorts, or a net jersey. Take off the helmet or tight-fitting clothing whenever possible.
Learn more about heat illnesses and other sports and fitness related illnesses and injuries in the Sports Injury Specialist Course.