Heat exposure, heat strain, and off-work recovery of Guatemalan sugarcane workers.

Abstract

Background: Agricultural workers are at high risk for heat related illnesses when performing heavy labor in hot conditions. Occupational heat strain, the physiological response to heat stress, is hypothesized to be common in this worker population but has rarely been measured objectively through core body temperature (Tc). The objective of this study was two-fold 1) evaluate workday heat strain and 2) examine the trajectory of heat exposure and Tc from the workday through the off-work hours to advance understanding of the recovery process and conditions of heat-exposed agricultural workers. Methods: Among 55 male Guatemalan agricultural workers, individual heat exposure (using ambient temperature loggers) and Tc (via an ingestible pill) were measured across a 24-hour period including workday and off-work hours. Urine samples were collected to assess hydration status on and off-work. Workers reported off-work activities, hydration practices, sleep, and nutrition through a survey. Data were summarized using descriptive statistics and visualizations. Results: Workers experienced excessive heat strain (44% with Tc > 38.0 °C, 16% with Tc > 38.3 °C, and 6% with Tc > 38.5 °C) during the workday. Approximately 29% achieved a higher maximal Tc during off-work hours than during the workday. Nearly 15% of workers reported sleeping < 7 hours. Discussion: There is a need to understand off-work conditions, practices, and resources available to workers to mitigate heat strain and related illnesses. Heat stress and Tc monitoring should extend to post-work shift for assessment of workers' physiological recovery and to inform more comprehensive interventions to protect worker health.