Exercising in the heat

Exercising during the summer heat can be challenging. The intense heat can seriously affect our performance, and this is compounded if the humidity is high. Thus, when we are exercising, we need to prevent our body temperature from rising excessively to mitigate the deleterious effects of dehydration.

One of the best ways to decrease the risk of developing heat illness or heat injury is to wear cotton outfits and gradually acclimate to exercising in hot environment. Our first exercise session can be as short as 10 minutes, and then gradually increase the duration as we become more tolerant of the heat. Along with heat acclimation, adequate hydration is essential to prevent the adverse side effects of exercise when the temperature and/or humidity are high.

Progressive dehydration occurs during exercise when sweating is profuse. As little as two per cent dehydration in our body weight during exercise can cause impaired temperature regulation. Thus, we should drink fluid before, during and after we exercise. Six to eight ounces of water, at 15-minute intervals during exercise, is recommended.

Heat cramps

When we are exercising in hot, humid, weather conditions, we need to safeguard against heat cramps, heat exhaustion and heat stroke. The symptoms of heat cramps include muscle spasm and muscle twitching in the legs, arms and abdomen. The best way to relieved these is to stop exercising, get out of the heat, massage the painful area, stretch slowly and drink plenty fluids.

Heat exhaustion results in fainting, dizziness, profuse sweating, cold clammy skin, overall weakness, headache and a rapid weak pulse. Heat exhaustion can be reversed if we stop exercising and find a cool place to rest and drink cool water. Loosen or remove clothing to speed up heat loss, and rub the body with a cool wet towel or ice pack. Lie on the back and elevate legs eight to 12 inches. If it last for more than half an hour, medical attention should be sought immediately.

Heat stroke

Heat stroke causes disorien-tation, warm dry skin, no sweating, a rapid full pulse, vomiting, diarrhoea, unconsciousness and high body temperature. The high body temperature can cause anxiety to set in. Even with a high temperature we may feel cold and develop goose bumps. Nausea, throbbing in the temples and numbness in arms and legs are also associated with heat stroke. The loss of fine motor skills and muscle weakness indicate nervous-system damage.

Heat stroke requires emergency medical attention. However, until this is available get the individual into a cool area, spray cool water over the body, and buff with a cool wet towel. If possible, place a cold pack on the head, neck, arm pit and groin. Adequate water replacement is the most important factor in preventing heat disorder. It is needed to maintain blood volume so that our circulation and sweating can proceed at normal levels.

Dr Kenneth Gardner is an exercise physiologist at Holiday Hills Research Center; email: yourhealth@gleanerjm.com.