I have witnessed two individuals experience the early phases of exertional heat illness - a spectrum of conditions that, if left unchecked, can be potentially life-threatening.  Both episodes were in children.  Both occurred during summer camp, one a general day camp and the other a sport camp.  

     As you exercise, your body produces sweat in order to regulate body temperature.  As the sweat evaporates it cools your body.  Exercising during hot and humid weather inhibits the effectiveness of this process which can result in your body temperature reaching above normal levels.  When the heat stress exceeds your body's ability to dissipate the heat, and therefore maintain a normal core temperature, heat illness can result.  

     You are most susceptible to developing heat illness during the first few days of warm/hot weather when your body has not yet acclimated to the higher temperatures.  In addition to the excessive demands placed on your body's thermoregulatory system by the hot and humid environment, dehydration can compound the situation either directly or indirectly.  Heat illnesses can be minor and easily reversible, such as with muscle cramps, or they can be life threatening, such as with heat stroke.  

     Children are especially susceptible to developing heat illnesses because they have immature thermoregulatory systems.  It takes longer for children to start sweating compared to adults; and, the rate at which they produce sweat is not as fast.  Furthermore, children have a greater surface area to body mass ratio in comparison so when they are exposed to a hot environment, they gain heat more quickly.  Below is a list of heat related illnesses and their associated symptoms.

Heat Cramps:  These commonly occur following intense exercise of a prolonged duration.

• Painful involuntary muscle spasm/contraction
• Occur in muscles of the abdomen, legs, and arms
• Caused by dehydration and electrolyte imbalance
• Relieved by rest, prolonged stretching, and fluid and electrolyte replacement

Heat Exhaustion:  The most common form of heat illness.  It can occur during or after exercise.  It is characterized as the inability to continue physical activity.  Individuals experiencing heat exhaustion have core body temperatures that range from 97 degrees to 104 degrees Fahrenheit (36 degrees to 40 degrees Celsius).

• Pale, sweaty skin
• Dizziness
• Weakness
• Decreased muscle coordination
• Nausea
• Vomiting
• Diarrhea
• Headache
• Irritability
• Chills
• Treatment involves moving affected individual to a shaded or air conditioned area.  Feet should be elevated while in the supine (on the back) position.  Excess clothes should be removed and fluids given.  Medical attention should be sought if symptoms do not resolve.

Heat Stroke:  A medical emergency that can result in death.  It requires immediate treatment.  Associated with body core temperatures exceeding 104 degrees Fahrenheit (40 degress Celsius).

• Disoriented
• Irrational behavior
• Loss of muscle coordination and balance
• Fast breathing (hyperventilation)
• Rapid heart rate (tachycardia)
• Low blood pressure (hypotension)
• Vomiting
• Diarrhea
• Seizures
• Collapse/coma
• Treatment involves whole body cooling in the form of cold water and ice water immersion therapy.

Tips to Reduce your Child's Risk at Camp:

• Make sure your child is adequately hydrated before going to camp.  Serve a breakfast that includes a beverage and foods with a high water content such as fruit (watermelon, oranges, etc.).
• Send a water bottle/sports drink for consumption during the day.
• Pack an extra beverage and foods with a high water content for lunch.
• Have your child dress in loose-fitting, light-colored and light-weight (e.g. mesh) clothing.
• Talk to the camp counselor/coach to ensure adequate water and rest breaks will be taken throughout the day.
• Confirm that camp counselors/coaches are familiar with the signs and symptoms of heat illnesses and that they are prepared and equipped to take the necessary action if a situation arises.
• Inquire about the camp's protocol for high-risk days (Wet Bulb Globe Temperature greater than 82 degrees Fahrenheit [28 degrees Celsius]).  For example, will they decrease the intensity and/or length of events involving physical activity?  Will they move sessions to indoors where there is air conditioning?
• If possible, choose a sport camp that offers sessions in the early morning before temperatures get too high.

     Summer day and sport camps should be an enjoyable and rewarding experience for your child.  Increasing your awareness of the signs and symptoms of heat illnesses, as well as how to avoid these conditions from occurring, will help to prevent a negative experience for both you and your child this summer.  

Resources:

ACSM's Guidelines for Exercise Testing and Prescription, Eighth Edition.

ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription, Sixth Edition.

ACSM's 2007 Position Stand: "Exertional Heat Illness during Training and Competition," Medicine & Science in Sports & Exercise.