By Trish Palmer M.D.
Member AMSSM

In general, triathletes enjoy competing in warm weather. Heat, however, can cause medical problems. Heat illnesses encompass a spectrum of medical problems from heat cramps and syncope (fainting), to heat exhaustion and heat stroke. These problems range from mild discomfort to sudden death.

Heat cramps are the simplest and probably most common of all the heat illnesses. The exact reasons that triathletes may suffer from heat cramps is not clear. It may be related to sodium imbalance, dehydration, or fatigue-induced chemical changes. Most triathletes have had cramps in their legs, the “charlie horse” feeling that happens often in the calf. It may also happen in the arms or in the abdomen. This can also manifest as vomiting (intestinal cramping).

Heat syncope is fainting, usually at the finish line of the race. It happens at the end of the race because the triathlete stops exercising, stopping use of their leg muscles. These muscles are used to pump your blood up from your feet, so stopping creates pooling of blood into the legs, and away from the brain. You feel dizzy, or lightheaded, and sometimes actually faint. Fainting is the body’s natural way of getting blood back to your brain by forcing a laying down position. A way to prevent this is to keep moving at the end of the race, no matter how exhausted you feel. If you keep your legs moving, fainting is much less likely to happen. That is why the medical staff will hang out at the finish line and yell at triathletes to keep moving. This may look like dehydration, but IV fluids are not helpful to treat this problem.

Heat exhaustion is defined by several symptoms: temperature <105 degrees F, flushed skin, chills, abdominal cramps/vomiting, goose bumps, dizziness, irritability, speech difficulties, fatigue, difficulty catching your breath, tingling, headache, and muscles spasms. Many people have felt these symptoms during or shortly after competition. Heat stroke differs from heat exhaustion in that the temperature is elevated above 105F, and the triathlete will have mental changes. Both of these heat illnesses need quick medical attention to prevent potential death.

General risk factors for heat illnesses include previous heat stroke, current fever, increased heat load (high temperature, intense sunlight, overexertion, drugs used to treat medical problems such as attention deficit, narcolepsy, and eating disorders, and over-the-counter stimulants such as ephedra or caffeine, most diet drugs, and most allergy medications) or difficulty with heat dissipation (high humidity in the environment and overdressing which limit evaporation, dehydration, lack of acclimatization, skin problems such as a burn or rash, and drugs such as phenothiazines, antihistamines, and alcohol). Avoid all of these if possible. Sports Medicine trained physicians may be able to help you through any of these issues for optimal training and performance.

To prevent heat illness, make a plan ahead of time. Proper hydration includes ingesting both water and sugar and electrolyte containing beverages, both before and during practices and races. Wearing layers of clothing that may be peeled off as you get sweaty or warm helps to dissipate heat. Try to train early or late in day when have you have less direct sun, and potentially cooler temperature. If you are traveling to a different climate to compete, take enough time to acclimatize, usually 3-5 days.

To treat heat illnesses, remember a few ideas. Keep moving at finish line to prevent heat syncope. Hydrate before, during and after practices and races. Train many months in advance to get into shape for any races. Try to find shade whenever it is available. Strip off wet clothing in high humidity.

Be smart, train well, and good luck!

Trish Palmer M.D.
Member AMSSM