Hydration Status In Construction Workers During A Regular Summer Workday

Occupational heat stress increases sweat production, which can lead to dehydration if fluid intake is insufficient. A previous pilot study observation during a regular summer workday suggested that construction workers often arrive at a worksite in a dehydrated state but do not experience further dehydration during their shifts. This finding raises questions about whether these observations can be replicated in a larger cohort and whether hydration status differs throughout the workweek. PURPOSE: The primary purpose of this study was to examine the impact of a work shift on the hydration status of construction workers in the summer. A secondary purpose was to compare the pre-shift hydration status across the days of the week (from Tuesday to Saturday) to determine whether workers were arriving more dehydrated as the week progressed. METHODS: A total of 189 construction workers (including 8 females) employed at a large construction site exposed to non-air-conditioning in covered and uncovered areas were recruited. Hydration status was assessed in each participant over a single workday. Data collection took place from Tuesday to Saturday during the summer of 2024. Hydration status was determined using pre- and post-shift measurements of urine specific gravity (USG). Heat index (HI) was recorded from different areas of the worksite throughout the workday. RESULTS: 56% of the workers arrived at the worksite dehydrated (USG ≥ 1.020) (1.021 ± 0.007). After the work shift, 54% remained dehydrated (1.021 ± 0.008), with no significant difference observed pre- versus post-work shift (p = 0.611). No significant difference (p = 0.142) among the days for pre-work-shift USG was observed (Tuesday 1.018 ± 0.007, Wednesday 1.020 ± 0.006, Thursday 1.022 ± 0.006, Friday 1.020 ± 0.007, and Saturday 1.022 ± 0.009). Average and peak HI were 24.7 and 25.5 °C on Tuesday, 32.7 and 37.4 °C on Wednesday, 36.3 and 43.3 °C on Thursday, 35.5 and 41.6 °C on Friday, and 33.3 and 39.5 °C on Saturday, respectively. CONCLUSION: Consistent with our previous pilot study, a majority of the construction workers arrived at the worksite dehydrated, but their hydration status did not significantly worsen during the work shift. Additionally, dehydration was not different across the days of the week, even with an increase in environmental temperature on some days. Supported by: Turner Construction Company Foundation and R01OH11528