Heat strain in road construction workers during the summer in New Mexico: a preliminary study

In the summer season, road construction workers perform physically demanding tasks outdoors, placing them at greater risk for exertional heat illness conditions. Assessing core temperature (Tcore) is critical as it serves as a key indicator of heat strain and helps to estimate the risk of heat-related illness. Despite the increased risk of hyperthermia, previous research has not assessed Tcore in road construction workers in the United States during summer work. Purpose: To report heat strain and environmental heat stress in a pilot study of road construction workers during work in the summer. Methods: Seven male road construction workers in New Mexico were observed performing physically demanding work during a summer work shift. Environmental heat stress (heat index [HI], dry/wet bulb temperature, and relative humidity), Tcore, and skin temperature (Tskin) were measured continuously at a single job site throughout the workday. Hydration was assessed pre- and post-shift via measurements of urine specific gravity (USG) and changes in body weight. Results: The peak HI recorded throughout the workday was 34.1 degrees C, corresponding to a "warning" heat risk level according to the Occupational Safety and Health Administration Heat Safety Tool App. Two of seven (29%) workers reached a peak Tcore of greater than 38.0 degrees C, and 4 (57%) began the work shift dehydrated, indicated by a USG >1.020. Conclusions: Findings from this pilot study suggest that road construction workers may begin their shifts dehydrated and some experience moderate hyperthermia while performing physically demanding work in hot environmental conditions.