Selena Deleon – THE WORKOUT For those of us who are determined to achieve that summer body even during the extreme summer heat, there are a few important precautions to follow.
UNDER RESTING conditions, the body's core temperature is about 37 degrees Celsius. What is important to note is that there must always be a balance between heat production and heat loss. When exercise is done, the body produces heat, which raises the core temperature. If most of this added heat is not lost, then the body's temperature might rise quickly to dangerous levels. Our core temperature is within a few degrees of a value that could lead to death by heat injury. Environmental heat stress combined with exercise poses the risk of hyperthermia which leads to heat exhaustion and heat stroke. The body has an automatic heat-loss mechanism which is responsible for regulating the temperature of your body during exercise.
HEAT LOSS MECHANISMS
Heat is lost from the body by four processes:
1. Radiation the transfer of heat from one object to another with no physical contact.
2. Conduction the transfer of heat from one object to another by direct contact.
3. Convection the transfer of heat from an object to air (or water), or vice versa, heat from the air or water can be transferred to an object.
4. Evaporation process by which heat causes liquid to be converted to a gas.
Heat loss depends on the temperature gradient among other things. When the temperature outside is higher than ours, we feel the heat coming from the air by convection, and the body tries to regulate its core temperature by sweating (sweat that evaporates cools the body). If we add exercise into the mix, then the body has to work even harder at keeping its core temperature at an acceptable level, and the role that evaporation plays becomes even more important.
In strenuous exercise and hot environments, evaporation is the most important process for losing heat and maintaining body temperature in the safe range. It is of utmost importance to stay hydrated, the more you drink is the more sweat you can produce. Wear cool, permeable clothing, leaving as much skin surface exposed to help with evaporation which will keep you cool. Factors that affect sweat production (dehydration) or interfere with the evaporation of sweat (impermeable clothing) are directly related to how efficiently the body can lose heat.
ACCLIMATISATION
People who exercise regularly in hot and humid environments become acclimatised in as little as seven to 12 days. Physiological adaptations such as a higher sweat rate, an earlier on-set of sweating, a reduced blood flow to the skin and a reduction of salt loss in sweat are a few examples of how the body improves its heat tolerance during exercise. As a result, the trained individual's body temperature stays lower during exercise.
Another way that you can influence your susceptibility to heat injury is to get fit. The fitter you are, the lower your risk of heat injury, as you are able to acclimatise faster and are able to tolerate more work in the heat.
Selena DeLeon is a certified professional trainer.
