When The Heat is On

Although summer is quickly coming to an end, there are still many hot and humid days ahead. Those hot, humid days greatly increase the risk of heat-related illnesses in physically active children and adolescents. Let’s take a few minutes to review the types of heat-related illnesses, appropriate first aid, and most importantly, prevention.

Exertional Heat Stroke

Exertional heat stroke (EHS) is a medical emergency that can occur quickly and progress rapidly if not treated. The primary cause of EHS is high-intensity exercise, especially for prolonged periods of time. This can be compounded by wearing equipment, lack of acclimatization, and hot or humid environments. Cardinal signs of EHS are an elevated core body temperature (above 104°F) and altered central nervous system function (change in level of consciousness, collapse, disorientation, incoherent speech, change in personality, convulsions). These may also be accompanied by nausea or vomiting, diarrhea, headache, and increased breathing and pulse. A common misconception is that victims of heat stroke will have hot, dry skin; while this may be true with classic (non-exertional) heat stroke, EHS victims will often be sweating profusely. Remember that core body temperature cannot be accurately measured through oral, tympanic, and axillary (underarm) thermometers as they typically read lower than true core temperature. Rectal temperature is considered the gold standard but is not always possible. If you’re concerned that an athlete may be suffering from EHS and you cannot obtain a rectal temperature, activate EMS and begin first-aid.

First-aid for EHS is simple—full body immersion in cold water (35-60°F) and activation of EMS. This should occur immediately and before transporting the victim to a hospital. Full body immersion can be accomplished in a cold tub, kiddy pool, or shower after removing all equipment and unneeded clothing. The athlete should NEVER be left unattended during immersion and first-aiders should monitor vital signs and level of consciousness until EMS arrives. When the athlete begins shivering (after several minutes), he or she should be removed from the cold water and monitored until EMS arrives. Cool, clear fluids may be given when the athlete is removed from immersion if he or she is fully conscious and able to drink independently. NEVER attempt to give oral fluids to a person who is semi- or unconscious.

Exertional Heat Exhaustion

Exertional heat exhaustion (EHE) is essentially a precursor to exertional heat stroke. It involves a slightly elevated core body temperature (99-104°F) and a decreased ability or inability to continue exercise. There can also be fluid, sodium, and energy depletion components. Other signs of EHE include pale skin, weakness, dizziness, headache, decreased appetite, nausea, vomiting, and diarrhea. The main recognizable difference between EHS and EHE is the altered mental status that occurs with exertional heat stroke.

First-aid includes removing equipment and unnecessary clothing, moving the athlete to a cool place (air conditioned or at least in the shade), beginning fluid replacement with cool liquids such as water or sports drink, and cooling the athlete with ice bags, fans, and cold towels. If the victim does not begin to recover quickly, activate EMS, consult your primary care physician, or transport the child to an emergency medical facility.

Exertional Hyponatremia

Exertional hyponatremia occurs when a physically active person suffers a fluid-electrolyte imbalance, namely too much water and not enough sodium in the blood. Exercise in the heat often results in large losses of both sodium and water through sweating. Exertional hyponatremia happens when an athlete does not ingest enough sodium to replace what is lost in sweat, or when an athlete drinks too much fluid without proper sodium replacement. Symptoms mimic those of exertional heat stroke, except that the victim is not overheated. They may include changes in mental status, nausea, vomiting, diarrhea, headache, physical exhaustion, muscular weakness, and disorientation or confusion. Athletes on low sodium diets and those who drink strictly water are particularly at risk. “Salty sweaters” are also at a greater risk—individuals who have a higher sodium content in their sweat. A good way to determine if an athlete is a salty sweater is to have him work out in a cotton t-shirt until it is saturated, remove the shirt while wet, and hang to dry overnight. Once dry, shake the shirt out; if a white cloud appears, the athlete is most likely a salty sweater. It is also important to remember that fluid-electrolyte imbalances can occur over a period of days, such as during tournaments and two-a-day practices.

First-aid for exertional hyponatremia includes transport to an emergency facility or activation of EMS if the athlete’s mental status has changed significantly. This allows medical professionals to determine the level of sodium replacement needed and the best way to deliver it.

Prevention of Heat-Related Illnesses

The best treatment for any illness is to prevent it from happening altogether and heat-related illnesses are no exception. Encourage kids to listen to their bodies when it comes to thirst and exercise intensity. New research has shown that drinking to thirst is the best way to ensure an athlete maintains appropriate fluid balance in the body during physical activity. Rehydration should also continue between events or practices. Eating a good diet is very important in hot weather, especially when exercising in the heat for a period of days. Athletes should salt their food generously (unless they have an underlying medical condition or family history of high blood pressure) and choose foods that have high sodium content, such as pizza, soup, and pretzels. This is especially true for salty sweaters. This salty diet can be altered back to “normal” once the weather cools down or athletes aren’t exercising for long periods of time on successive days.

Frequent rest breaks are important in hot, humid weather to allow the body to dissipate heat and the athlete to drink when thirsty. Athletes should be permitted to remove helmets and other equipment during rest breaks if possible. When exercising in hot weather, ten minute breaks every 20-30 minutes are recommended and athletes should be allowed free access to fluids.

Gradually acclimating to the heat over a period of two weeks is extremely important and allows the body to make physiological changes and better tolerate exercise in hot environments. If a child is taking medications, consult your primary care physician to determine if they could increase the risk for heat-related illnesses.

Heat-related illnesses are an inherent danger when exercising outdoors in the summer. But always remember…an ounce of prevention is worth a pound of cure! Hopefully the above information will help you and your young athlete take adequate precautions and have a safe, happy, and healthy summer and fall season.

Consult your primary care physician for more serious injuries that do not respond to basic first aid. As an added resource, the staff at Nationwide Children’s Hospital Sports Medicine is available to diagnose and treat sports-related injuries for youth or adolescent athletes. Services are now available in five locations. To make an appointment, call (614) 355-6000 or request an appointment online.