Heat Stress in Aviation

INTRODUCTION It is generally agreed that man’s adaptations to the heat are well developed, conversely when naked in the cold his physiological adjustment very poor. It could also be argued that humans are historically tropical as: They rely on physiological adjustment in the heat but behavioral adjustments in the cold. The thermo-neutral ambient temperature for nude humans and the temperature necessary for undisturbed sleep is high at 27c and humans have substantial physiological adjustments to the heat but modest cold acclimmatisation. BACKGROUND Temperature regulation is a classic example of a biological control system. The balance between heat production and heat loss is continuously being disturbed, either by changes in metabolic rate (exercise or work being the most powerful influence) or by changes in the external environment, which alters heat loss. These resulting changes in body temperature can adversely effect the function of body systems and organs. As a result, heat production or heat loss processes are triggered in order to restore normal body temperature. If the heat generating systems of the body are excessive, as is the environment, then the capacity of the body to maintain thermal homeostasis is exceeded and can lead to a serious threat to health, or even death. In addition this health deficit severely effect an individuals capacity to work optimally, the end result is poor health and cognition. Strategies to minimise or eliminate this effort will benefit the performance of persons working in the aviation industry.