Heat stress vulnerability in indoor and outdoor occupations

Introduction:  Western India confronts with extreme heat wave situations at regular frequency during the summer months. The study refers to vulnerability assessment of workers to hot environment in indoor and outdoor working conditions.    

Methods:  The study was conducted among iron, ceramics and pottery (CP), power loom, pulp and paper (PP) mill and stone quarry (SQ) workers (N=999). The perceptions of the workers to heat-related signs and symptoms were examined. The wet bulb globe temperature index and physiological responses were recorded.    

Results:  The dry-bulb temperatures exceeded 40OC for 3/4th of the total observations recorded in iron works, 1/4th in CP, PP, and over 1/3rd in SQ works; all observations in power loom exceeded 40OC. The WBGT values in power loom was highest (35-37OC), followed by CP, SQ, PP, and iron works. The SQ workers had higher signs and symptoms of heat strains, including excessive sweating, tachycardia, elevated body temperature, muscle cramps and mental disorientation. About 2/3rd of the iron, CP and power loom workers complained of elevated body temperature and loss of working capacity. The principal component analysis elucidated the behavioural responses into four component structures (PC-1 to PC-4 - muscle cramps, thermal stress, thermoregulatory and generalized responses), explaining half of the total variance for iron, CP, power loom and SQ workers.    

Discussion:   Internal thermal stability and behavioural adaptations are critical to manifest ones environmental warmth. The perception dimensions indicated that the outdoor stone quarry works were strenuous; the indoor works, such as iron works and power loom were inevitably hot workplaces. The stone quarry workers faced greater risk, as compared to power loom, ceramic and pottery, and iron workers.