Skin Temperature Variation and Thermoregulatory Responses to Environmental Heat Stress Among Market Workers in Onitsha, Anambra State

Occupational heat exposure presents a significant physiological challenge for outdoor workers in Nigeria, particularly in commercial markets with limited ventilation and high ambient temperatures. This study assessed skin temperature variation and thermoregulatory responses to environmental heat stress among market workers in Onitsha, Anambra State, South East Nigeria. Eighty market traders were recruited from the Onitsha Main Market, and skin temperatures at the forehead, forearm, and chest were measured using a non-contact infrared thermometer during morning, midday, and afternoon shifts. Ambient temperature and relative humidity were simultaneously recorded. Heart rate, sweat rate, and perceived thermal comfort were also assessed. Descriptive statistics and paired t-tests were applied to compare time-point differences. Results showed significant elevation in skin temperature and heart rate between morning and midday sessions, with midday ambient temperatures averaging 36.2 degrees Celsius. Sweat rate was highest among male traders and those engaged in physically demanding tasks such as lifting and packing. Perceived discomfort scores were highest during midday hours. The study concludes that market workers in Onitsha are exposed to significant heat stress that elicits meaningful thermoregulatory responses. Workplace modifications including shading structures, hydration access, and shift scheduling are recommended to reduce heat-related physiological strain. Keywords: heat stress, thermoregulation, skin temperature, market workers, Onitsha.