Effects of Heat on Behavioral and Physiological Mechanisms of the Human Thermoregulatory System During Rest, Exercise, and Work

The aim of this thesis is to extend the current understanding of the impacts of heat stress on human physiology, cognition, behaviour, and capacity to perform physical work. In this respect, we conducted two systematic reviews and collected numerous data from hundreds of individuals who perform physical work in various environments. A series of field observations and interventions followed by experiments in laboratory settings, took place in Cyprus, Denmark, Greece, Qatar, and Spain. Additional datasets were provided from Australia, Canada, Slovenia, and the United States of America. This work led to seven studies which are presented as different chapters of the current thesis. Summarizing, the results of the current thesis show that environmental heat stress affects human health, physiology, cognition, and capacity to perform manual work, leading to significant economic implications which are projected to rise during the next decades. Performing manual work under the sun leads to added heat strain and more compromised cognitive function, even in circumstances when heat exposure is considered to be of the same intensity as performing manual work in shade. Encouraging individuals who perform work in the heat to self-pace must be a key element of any effective heat mitigation strategy. Additionally, interventions such as mechanization, work-rest cycles, hydration strategies, ice slurry consumption, and clothing strategies could play a significant role as a protective barrier against environmental heat stress. The use of appropriate thermal indices could act as an additional proactive measure aiming to protect human health and wellbeing.