Q: What steps can an individual take to avoid heat injury when exercising in a hot environment?
A: A potential health hazard of exercising in warm weather exercise is heat injury.
A key point to remember is that anyone who exercises in a hot environment is susceptible to heat injury. In the excessively warm and often humid conditions that frequently occur in the summer and early fall, heat stress can be a real threat for individuals who engage in aerobic-type exercise activities - either outdoors or indoors in facilities without air conditioning.
Individuals exercising in a warm, humid environment should adhere to five relatively basic guidelines to avoid heat injury.
First, make sure that they are adequately hydrated. This can be accomplished by consuming copious amounts of fluid (just short of feeling fully bloated) thirty minutes before exercise, drinking at least six ounces of fluid after approximately every 20 minutes of exercise, and drinking beyond thirst cessation during the recovery period.
Water is generally considered the best hydration fluid unless the duration of the exercise bout exceeds 60 minutes. If an individual exercises for longer than an hour, a sports drink (e.g., Gatorade or PowerAde) may be the more beneficial.
Second, an individual should become acclimatized to the environment. Acclimatization, the body's gradual adaptation to changes in environment (it usually takes 10-14 days of heat exposure combined with exercise), can greatly reduce an individual's risk for heat injury.
Following acclimatization, individuals will sweat sooner, produce more sweat, and lose fewer electrolytes in their sweat. The net effects of acclimatization are a lower body core temperature, a decreased heart rate response to exercise, and a diminished potential for dehydration and electrolyte depletion.
Third, individuals should lower the intensity level of their exercise bout (especially during the acclimatization period) because this step will decrease the heat load and reduce the strain on their thermoregulatory mechanisms.
Fourth, individuals should never wear clothing that is impermeable to water (e.g., rubberized sweat suits), since such clothing prevents the evaporation of sweat from the skin and thereby increase the risk of heat injury.
Fifth, every individual should respect the existing environmental conditions since temperature and relative humidity can greatly influence both the degree of heat stress and the body's ability to effectively respond to the heat stress.
As a general rule of thumb, an individual should consider curtailing exercise when the ambient temperature is above 90 degrees Fahrenheit and, concurrently, the relative humidity is above 60 percent.
In summation, warm weather exercisers should adhere to the following motto: "Drink up, slow down, and have fun exercising."
Bryant, Cedric X. 101 Frequently Asked Questions about "Health & Fitness" and "Nutrition & Weight Control". Sagamore Publishing, 1999.
for ACE's FREE e-newsletter for fitness enthusiasts.