By Brandon Pollock, PhD, ACSM-EP-C
Summer is right around the corner, what better time than now to review some fundamental considerations for preparing to exercise/ perform physical activity in a hot environment,
Compared to exercising in ambient temperature, when exercising in the heat you are at greater risk of heat related illness. Attention should be spent when preparing to exercise in the heat.
A healthy person responds to heat exposure in two different ways:
The voluntary responses to heat stress are the conscious behavioral modifications made by an individual in an effort to reduce their body temperature, such as resting, changing into lighter clothes, drinking a cold drink, or sitting in front of a fan.
The non-voluntary responses to heat stress are initiated when thermoreceptors (temperature sensing receptors) detect a rise in body temperature. Thermoreceptors then signal the temperature regulation center located in the brain, the hypothalamus, which responds by initiating several different physiological modifications including vessel dilation, sweat gland activation, and reduced metabolic rate. Together these processes increase body heat loss, decrease body heat production, and ultimately decrease overall body temperature. Collectively, the voluntary and non-voluntary responses to thermal stress (hot or cold) made in an effort to maintain normal body temperature are a process known as thermoregulation.
Many factors influence thermoregulation in the elderly(ages 65 and above). An elderly person’s ability to ‘thermoregulate' themselves maybe reduced. The process of aging slows the speed of signals sent to the nervous system, resulting in both impaired voluntary and non-voluntary responses to heat stress, and ultimately a reduction in thermoregulation. In general, seniors are less likely to sense and respond to changes in temperature. According to the Centers for Disease Control and Prevention (CDC), this may put them at greater risk of developing heat related illness. Special care must be taken into account when these individuals wish to exercise in a hot environment.
Seniors with chronic illnesses such as heart disease should avoid exercising in heat if possible, but for seniors brave enough, here are some tips:
Stay hydrated. Before, during, and after your workout. If you exercise longer than 60 minutes choose a drink containing electrolytes.
Dress appropriately. Wear loose fitting, light clothes. This will promote sweating and keep your body cool. As an added precaution it is always a good habit to bring an extra set of clothes.
Weight yourself before and after your workout. This will help you have an idea as to how much water you need to drink.
Keep an eye out for symptoms of heat related illness. Symptoms of dehydration frequently begin in the lower body, and can be either painful tightening in the legs, muscle spasms, or heat cramps. If you experience symptoms such as unusual fatigue, weakness, dizziness, or rapid heartbeat; immediately stop exercise and move to a cool area.
If added precautions are taken, exercising in the heat can be an effective, fun, safe, workout for anyone, including seniors. But because of their increased risk of developing heat related illness, it is very important for seniors to understand how to appropriately prepare for exercise in a hot environment.
Article Resources
1) http://www.cdc.gov/
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3) Guyton, A.C. 1996. Body Temperature, Temperature Regualation and Fever, 911-922. Textbook of Medical Physiology, W.B. Saunders Company, Philadelphia.
4) Yousef MK, Dill DB, Vitez TS, Hillyard SD, Goldman AS. Thermoregulatory responses to desert heat: age, race and sex. Journal of gerontology. Jul 1984;39(4):406-414.