Hydration Status in Construction Workers During a Regular Summer Workday

Occupational heat exposure increases sweat production, which can potentially lead to dehydration. A previous pilot study observation during a regular summer workday suggested that construction workers arrive at the worksite in a dehydrated state but do not experience further dehydration during their shift. This finding raises questions about whether these observations can be replicated in a larger cohort and whether hydration status declines progressively 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 during the summer were recruited. Each participant was assigned to a single-day hydration status assessment, providing urine samples before and after their work shift. Data collection took place from Tuesday to Saturday. Hydration status was evaluated using pre- and post-shift measurements of urine specific gravity (USG). Heat index (HI) was recorded from different areas of the worksite. RESULTS: 56% of the workers arrived at the worksite dehydrated (USG ³ 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 statistical difference (p=0.142) among the days on pre-work-shift USG was observed on 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: As observed in our previous pilot study, the majority of the 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 heat stress on some days.