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In summertime, athletes, officials and even parents need to be aware of the effects on your body of exercising or working in hot and humid conditions, and the potential dangers to your health.

Normal functioning of the organs of the body requires internal body temperature to be maintained within very small limits around 37^oC. The body must cope with the heat continually produced by active muscles and environmental temperatures as high as 50^oC. The body 'keeps its cool' mainly through sweating.

In the heat, there is an increase in the blood flow to the skin, which is then cooled by the evaporation of sweat. In hot conditions, several liters of fluid can be lost in an afternoon or during a typical training session, equating to several kilograms of weight. In very humid conditions, the sweat does not evaporate but simply drips from the body, resulting in less effective cooling, and a greater loss of fluid. To help the body maintain correct temperature, and to prevent dehydration, this lost fluid must be continually replaced.

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Dehydration can cause a decrease in performance, as the reduced total volume of blood and the larger proportion of blood going to the skin results in less blood to the exercising muscles. Not only is there a potential decrease in performance, if left unattended dehydration can lead to heat exhaustion (weakness, uncoordination) and the more severe heat stroke (headache, absence of sweating, increased heart rate, and even death!). If someone is beginning to show signs of heat illness, the first response is to provide commonsense treatment: move the person out of the heat, and cool their body (cool drinks, sponging, fan).

Your body can become acclimatized to exercising in the heat, mainly through an increase in sweat rate, enabling more effective cooling. The dangers of heat illness are therefore greater early in summer, before the body has had a chance to become acclimatized. If people wear sensible clothing, take plenty of fluids, and recognize the dangers of exercising in the heat, then problems should never occur, and you will be able to have fun in the sun.

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Related Pages

• Exercise in Extreme Conditions — articles and information
• Exercising safely in heat
• Beach Exercises List
• Keep cool with these Water Workouts
• The Wet Bulb Globe Temperature (WBGT) — a measure of environmental conditions
• The Australian Open Tennis Heat Policy

Disclaimer

The above information is presented as a general guide. The author and publisher take no responsibility for any possible consequences of any treatment, procedure, exercise, action or application of medication based on this information. See more: Disclaimer.