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Abstract
The construction industry is one of the most hazardous sectors worldwide, characterized by dangerous working conditions, particularly in extreme environments such as high temperatures, which increase the prevalence of heat-related illnesses. These illnesses can severely impact workers' health and safety. Therefore, it is crucial to provide regular training to enhance workers' awareness of heat-related illnesses and equip them with the necessary skills to prevent such incidents. Additionally, there is a notable gap in research on specific factors such as early symptoms, cognitive impairment, and fatigue caused by heat on construction sites. This dissertation addresses this gap through four main studies. The first study evaluates the feasibility and benefits of using Evidence-Centered Design, an educational methodology, in designing a heat stress training program that increases workers’ knowledge, skills, and attitudes towards heat dangers. Subsequent studies involve experiments conducted at varying temperatures where participants performed labor tasks on a real construction site in the Southern USA. The first study assesses cognitive impairment in construction workers exposed to heat, using cognitive tests to measure workers' reactions, concentration, and memory. Results indicated a 16% to 35% decrease in cognitive responses throughout the workday, with a more significant decline in working memory as temperatures increase. The second study explores the effects of heat on workers' physical fatigue by monitoring core body temperature and their perceived exertion rates in real-time. Findings showed a 3-point increase in perceived exertion over the day and with increasing temperatures. Despite high core body temperatures, 35% of workers reported low exertion at times. The third study tracks early symptoms of heat-related illnesses, relating core body temperature, heart rate, and oxygen consumption alongside reported symptoms every 10 minutes. Initial findings included heavy sweating within the first 40 minutes, followed by shortness of breath, fatigue, and reddened skin. Notably, all participants exhibited symptoms after a core body temperature increase of 0.7°F to 1.0°F, with symptoms perceived even at lower temperatures. Research also suggests that oxygen consumption is more indicative of heat stress progression than core body temperature or heart rate.