Wai-Po Tang, 1997. Webpublish Dec 2001
heat stress during practice or competition can have direct result
on the athlete's performance and it may even lead to death in extreme
cases. Basically, when heat gain exceeds heat loss during intensive
exercise in warm environment, the core temperature rises. Whereas,
in a cold environment, the heat loss often exceeds heat production
thus lead to reduced core temperature.
balance to maintain normal core temperature of 37°C depends
on the regulatory factors of heat gain and heat loss. Heat gain
is affected by Basal Metabolic rate, muscular activity, hormones,
thermic effect of food, postural changes, and environment. Heat
loss is affected by the physical mechanisms of radiation, conduction,
convection and especially vaporisation of water from skin and the
create metabolic heat and disrupt the homeostasis of the body due
to the blood flow needed for the skin and the muscles. The muscles
require blood flow for oxygen supply and the skin demands blood
flow for heat dissipation.
E. and Boje, O. (1945) stated that, "Research on the relationship
between the rise in body temperature and exercise capacity has produced
conflicting results." The argument is that increased core and
muscle temperature signals a failing thermoregulatory mechanism
that reduces exercise performance. However, other researchers argued
that temperature increases might accelerate neuromuscular processes
and thus increase exercise capacity.
A subject is put under two conditions of free heat loss and restricted
heat loss on separate days over a period of two weeks to provide
data of thermoregulatory analysis. The data of the subject will
be examined to determine the effects of heart rate, core temperature
and effort. Thus, the results offer the opportunity to review or
argue the theses and the hypotheses as mentioned above.