Guest Post by:

Alec DeCastro, MD
Assistant Professor, MUSC Department of Family Medicine
Chief, Primary Care Sports Medicine

The summer is in full swing here in the Lowcountry!  July and August are on average the hottest months out of the year, and this is also the time of year that football players return to summer camp and conditioning.  As the temperatures continue to rise, it is important for all athletes to recognize the symptoms of heat illness while exercising in the summer sun. Even if you’re not planning on playing football or running outside, athletes must be smart before embarking on a summer workout. 

Heat illness is a spectrum that ranges from heat cramps, heat exhaustion, to heat stroke.  These conditions can occur suddenly due the risks of exercising in the heat.  Signs and symptoms can sometimes be mild, but it is important to recognize them early in order to prevent injury.  These include:

  • Dizziness
  • Fainting
  • Fatigue
  • Muscle cramps
  • Profuse sweating
  • Rapid pulse
  • Nausea
  • Pale skin

Certain risk factors can predispose you for sustaining a heat illness or injury.  Medical Conditions such as: heart disease, lung illnesses, kidney problems, obesity, high blood pressure, diabetes, pregnancy.  Exercise may improve these conditions, but always take the heat in account and consult your doctor or a sports medicine physician for specific advice.  Medications such as diuretics (water pills) or antihistamines may be dehydrating and should be avoided if it is too hot outside.   Infants up to the age of 4 or older adults > 65 should also use caution.

Heat illness may be easily prevented by some common sense precautions.  It is important to drink plenty of water prior to and during exercise in the heat.  Always limit caffeine and alcohol intake.  Also, dress cool with loose clothes that allow sweat to evaporate easily.  Don’t forget to wear sunscreen!

Another way to prevent heat illness is to be aware of the weather conditions.  A heat index is a better indicator than just the temperature alone.  At about a 60% humidity, our sweat stops evaporating and therefore our body doesn’t cool as easily.   A more accurate measure of humidity may be obtained by a Wet Bulb Globe thermometer (WBGT).  A simple chart for WBGT, which is used by the military, can guide sports teams on how to run summer practices and conditioning drills in this extreme heat.

Wet Bulb Globe Thermometer

If you or someone sustains a heat illness, get them out of the heat right away and bring them to an air conditioned building or the shade.  Let them rest and elevate their legs and feet.  Let them drink cool water

Another serious condition that may develop in the heat is called Rhabdomyolysis (Rhabdo).  Exertional rhabdo happens when there is damage to muscle caused by excessive unaccustomed exercise, especially in the extreme heat.  When muscle tissue works so hard, the fibers break down, causing an enzyme called CK to be released into the bloodstream.  In these cases, a lot of stress is placed on the kidney leading to kidney damage or even kidney failure.  The risk of rhabdo is markedly increased while exercising in hot, humid environments.  This condition is more common in football, and especially high intensity workouts such as cross-fit.  For example, in 2011, thirteen University of Iowa football players were hospitalized with rhabdo after a very intense workout.  Symptoms of rhabdo may be extreme muscle pain and soreness, or dark urine (brown, cola-colored).  In order to prevent rhabdo, athletes must hydrate before, during, and after workouts.  Make sure you don’t push yourself too hard until you get hurt.  If you have any of the symptoms, see a sports medicine doctor right away.

The most serious form of all the illnesses is heat stroke.  This a true medical emergency and happens when the body temperature reaches at least 104F.  Signs of heat stroke are:

  • Confusion
  • Lack of sweating (red, hot, dry skin)
  • Headache
  • Loss of consciousness

Heat stroke can damage the brain and other internal organs, so attempt to them cool right away with ice packs and call 911!  You may save a life!

With this in mind, exercise, get healthy, and enjoy the outdoors.  Please contact us at MUSC Sports Medicine for specific advice about you and exercising.

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