Heat Illness
by Marguerite Weston, M.D.
It is summertime in Oklahoma. As Oklahomans, we are used to a hot and humid summer. On average the high temperature in July and August is 93o in Oklahoma City with humidity around 80%. Although the season is a welcome change after the cold wind of winter and tornadoes of spring, it also brings with it some danger. According to the Center for Disease Control and Prevention, between 1979 and 2003 there were 8,015 deaths attributed to excessive heat exposure (that’s 334 per year!).
In general, as we exercise our core temperature increases and our bodies do several things to keep our temperature normal. We sweat which then evaporates and causes cooling of the skin. However, if the humidity is high this hinders evaporation. Dehydration of more than 3-5% of body weight will decrease sweat production and decrease blood flow to the skin, which will decrease heat dissipation. Dehydration or not drinking properly (such as only drinking water instead of sports drinks as well) can then cause electrolyte imbalances. This balance of heat production and heat dissipation keeps us healthy. If an imbalance occurs heat-associated illness may result.
Muscle cramping is a common heat related illness we see during the summer months especially in football camps, two-a-day practices, and long distance running. Cramps are a warning that you need to drink more! And a sports drink with electrolytes is better than water. If you cramp try to stretch (or have someone else stretch) the muscle. If you continue to cramp or begin having more diffuse cramping throughout your body you must let your coach or athletic trainer know as prolonged diffuse muscle cramping can be dangerous.
A second heat-associated illness is exertional heat exhaustion, which occurs when our bodies cannot get rid of the heat we make by exercising. This is the most common heat-related disorder seen among active populations. Once your core temperature increases you may have nausea, vomiting, headache, weakness or dizziness. Some people may even collapse, which some feel is a “safety brake” for the brain. Treatment for heat exhaustion includes moving the athlete to a cool area, removing clothing and trying to cool the athlete. You can place ice bags in the armpits and groin. Place the athlete on their back with the legs raised in the air. Oral hydration should be attempted if the patient is alert and has no vomiting or diarrhea. Watch for confusion or decreased alertness, and if changes occur or if they do not improve they must go to emergency department.
Finally, exertional heatstroke (EHS) is the second most common cause of death among high school athletes (second to spinal cord injuries). The definition of EHS is a rectal temperature of 104o F or greater and neurological changes (such as confusion, irritability, balance trouble, seizure). If not treated, EHS can affect all organ systems. The first symptoms are the same as those with heat exhaustion, however they continue to worsen and then develop mental changes. Treatment is immediate cooling of the entire body. During marathons or football camps we will often put athletes into ice baths. If treatment is delayed mortality can reach 80%, however with immediate cooling it can decrease to 10%. After a person has had a heat illness you are prone to a worse reaction to heat in the following weeks. Returning to play should be advised by your physician.
So what can you do to decrease your risk of heat illness?
• Clothing: where light colored clothing that wick water away from your body
• Weather: try not to exercise outside during peak hours (risk of heat illness increases as temperature exceeds 820 F) or peak humidity
• Hydration: drink plenty of fluids (not just water, include sports drinks as well). Don’t wait until you’re thirsty. Look at your urine; dark urine means you need more fluids.
• Weight: keeping track of your body weight will allow you to watch your hydration (most universities will not allow their football players to continue with two-a-day practices unless there body weight stays consistent)
• Acclimate: 10-14 days of heat acclimatization is needed to decrease your risk
What increases your risk of heat illness?
• Body mass index greater than 27 (kgm-2)
• Sickle cell trait/disease
• Certain medications (including anti-depressants and some allergy meds)
In general, heat illnesses can be prevented. If you are thinking about beginning an exercise regimen especially in the summer please see your doctor. Remember if you see any of the above mentioned symptoms please let your coach, athletic trainer or someone else know. If you have a player/athlete who is having these symptoms call 911 and try to cool them…it may save their life.