Stress has been described as a measure of cognitive, physical and biological response to any stressor. The stressor can be an event or stimuli which are perceived as a threat. Environmental stressors include a variety of physical stimuli, noise, temperature (heat and cold), pressure (hypobaric [altitude] and hyperbaric [underwater]), photoperiods (24 h darkness or light), and vibration alters a person’s ability to function. Impact of thermal stress is predominant on soldiers under desert conditions affecting their performance. Desert and jungle warfare and operational aspects have certain physiological implications. Man cannot adapt to low quantities of water permanently. The adapted soldier needs an equal quantity of water or at times more than the unacclimatized one. Detrimental effects of heat exposure are mainly attributed to excessive elevations in core body temperature. Normally, body temperature is maintained stable relatively by balancing body heat production [due to metabolism] with heat loss. Operating in desert is very difficult task to achieve. But, when there is an available chance to train in the desert this will be the best preparation for operating in this climate. In spite of being fit, soldier still need at least 10 to 12 days to get used to the desert climate so he can be ready to carry on the operation well. Heat stress management is critical for preventing heat casualties. Most importantly, leadership must fully inform personnel of the risk associated with heat stress.