Study Examines Heat Related Illness in High School Athletes

High school athletes are sidelined more than 9,000 days a year because of heat-related illnesses, according to a new CDC analysis.

The analysis, published in this week's Morbidity and Mortality Weekly Report, looked at 2005-2009 data from the National High School Sports-Related Injury Surveillance Study. The data covered nine sports and estimated national numbers based on a sample of 100 high schools.

Football was the sport associated with the most heat related illnesses and August was the most common month for them to occur, according to CDC's analysis. The report also found illnesses were most likely to occur during practice, not game time, and more likely to occur among overweight athletes.

The study looked at the incidence of "time-loss heat illness," defined as illness where a player needed at least one day to recover and missed time on the game field.

Heat-related illnesses included heat cramps, heat exhaustion, and heat stroke – a medical emergency that in the absence of prompt intervention can lead to loss of consciousness, or more permanent serious medical conditions such as neurologic, cardiac, renal, gastrointestinal, hematologic, or muscle dysfunction and subsequently death.

Since 1995, 31 high school football players have died from heat stroke, according to the National Center for Catastrophic Sports Injury Research.

"One death due to heat-related illness is too many," said Michael McGeehin, director of CDC's Division of Environmental Hazards and Health Effects. "Heat related illness is preventable; the more we know about how and when it happens, the better we can prepare people who maybe most at risk."

For more information, http://www.cdc.gov/Features/ExtremeHeat/ or visit the MMWR site at www.cdc.gov/mmwr.

~CDC (August 2010)

Exertional Heat-Related Illnesses 

Some sports injuries caused by contact or overuse are often accepted risks when a young person plays sports. However, “heat injury,” or illness resulting from excessive exercise in high temperature and humidity, is one type of sports injury that can almost always be prevented with proper attention to safety and common sense.

The 3 most common types of heat injury are:

  • Heat Cramps –

    Heat cramps are brief, severe cramps in the muscles of the legs, arms, or abdomen that may occur during or after vigorous exercise in extreme heat. The sweating that occurs with vigorous exercise causes the body to lose salts and fluids. And the low level of salts causes the muscles to cramp. Children are particularly susceptible to heat cramps when they haven't been drinking enough fluids. Although painful, heat cramps aren't serious.

    What to Do:

    Most heat cramps don't require special treatment. A cool place, rest, and fluids should ease your child's discomfort. Massaging cramped muscles may also help.

     

  • Heat Exhaustion –

    Heat exhaustion is a more severe heat illness that can occur when a person in a hot climate or environment hasn't been drinking enough fluids.Symptoms include high temperature (up to 104°F), weakness, nausea, vomiting, dizziness, confusion, and fainting.  Symptoms may also include:

    • dehydration

    • fatigue

    • weakness

    • clammy skin

    • headache

    • nausea and/or vomiting

    • hyperventilation (rapid breathing)

    • irritability

    What to Do:

    Treatment is to stop exercise, either sit or lie down, and cool down (fanning, cool towels, ice bags, move to shaded or air-conditioned area). Also, giving lots of fluids is essential. If symptoms do not stop quickly, the athlete should be taken to an emergency room right away. 

    • Bring your child indoors or into the shade.

    • Loosen or remove your child's clothing.

    • Encourage your child to eat and drink.

    • Give your child a bath in cool (not cold) water.

    • Call your child's doctor for further advice. If your child is too exhausted or ill to eat or drink, intravenous fluids may be necessary.

    If left untreated, heat exhaustion may escalate into heatstroke, which can be fatal.

     

  • Heat Stroke –

    The most severe form of heat illness, heatstroke is a life-threatening medical emergency. The body loses its ability to regulate its own temperature. Body temperature can soar to 106 degrees Fahrenheit (41.1 degrees Celsius) or even higher, leading to brain damage or even death if it isn't quickly treated. Prompt medical treatment is required to bring the body temperature under control. Athletes can have seizures or go into shock or coma. They should be taken to an emergency room immediately. 

    Factors that increase the risk for heatstroke include overdressing and extreme physical exertion in hot weather with inadequate fluid intake.

    Heatstroke can also happen when a child is left in, or becomes accidentally trapped in, a car on a hot day. When the outside temperature is 93 degrees Fahrenheit (33.9 degrees Celsius), the temperature inside a car can reach 125 degrees Fahrenheit (51.7 degrees Celsius) in just 20 minutes, quickly raising a child's body temperature to dangerous levels.

    What to Do:

    Call for emergency medical help if your child has been outside in the sun exercising for a long time and shows one or more of the following symptoms of heatstroke:

    • flushed, hot, dry skin with no sweating

    • temperature of 105 degrees Fahrenheit (40.6 degrees Celsius) or higher

    • severe, throbbing headache

    • weakness, dizziness, or confusion

    • sluggishness or fatigue

    • seizure

    • decreased responsiveness

    • loss of consciousness

    While waiting for help:

    • Get your child indoors or into the shade.

    • Undress your child and sponge or douse him or her with cool water.

    • Do not give fluids.

    An Ounce of Prevention

Some common-sense rules to ensure safe exercise in the heat are as follows:

  • Fluids - This is the most important way to prevent heat injury. Parents and coaches need to be sure children drink plenty of fluids before starting any exercise and that they continue to drink during exercise. A good starting point is about 4 to 6 ounces of fluid every 15 minutes for a 90-lb child. You should not depend on your child to tell you how much fluid he or she needs. Recording your child’s weight (without clothes) both before and after exercise can help you determine how much fluid your child needs and help you adjust the next day’s fluid intake. Athletes should weigh about the same before and after any activity. Cold water is fine for rehydration, but flavored sports drinks may stimulate your child to drink more. Fruit juices and soda are not good choices, as they contain too much sugar. Adding small amounts of salt to food is a good way to replace electrolytes, but avoid salt tablets, as they are irritating to the stomach and can be dangerous.
  • Environment – It is harder for the body to control heat when temperatures are higher than 80°F, especially when the humidity is higher than 70%. Direct sunlight, as well as hot, humid winds, can also increase risk. Parents and coaches must be responsible for decreasing or stopping practices or competitions during periods of excessive heat and humidity. Moving practices indoors or to a shady area can help reduce the risk of heat injury to an athlete. 
  • Clothing - Heavy protective equipment or covering too much of the skin can make it more difficult for the body to get rid of excess heat. Clothing should be light-weight and should expose as much of the skin as possible for evaporation of sweat. Wearing a hat can also help.
  • Acclimatization - This is the process by which the body gets used to exercising in the heat. The first 1 to 2 weeks of practice in hot, humid weather should start light and gradually increase in intensity. 
  • Medical Conditions - Anyone with acute illness (especially fever, vomiting, or diarrhea that can lead to dehydration) should avoid exercising in hot, humid conditions until the illness is completely gone. Children with chronic medical conditions (such as diabetes, cystic fibrosis, kidney disease) should talk to their pediatrician about how to maintain normal hydration. Certain medications (such as cold medicines) can make it harder for the body to get rid of heat and should be used as little as possible. Obesity (being overweight) can greatly increase the risk of heat injury. This is why preseason practice in late summer for larger athletes (such as football players) is especially risky. These athletes should start mild exercise early in the summer and slowly work up to full workouts. Last, anyone with a history of heat injury may be at increased risk for repeated injury and should pay extra attention to proper hydration and rest.
  • Knowledge - Know the symptoms of heat illness and watch for them in your child. When a player feels confused, dizzy, nauseated, sleepy, or otherwise seems ill during exercise in hot, humid weather, heat illness should be considered. Have the child cool down and start drinking right away. If you do not see quick recovery, take the child to an emergency room. It could save the child’s life.
     
    ~AAP