Heat Stress, Physiological Response, and Heat-Related Symptoms among Thai Sugarcane Workers

Abstract

Prolonged or intense exposure to heat can lead to a range of health effects. This study investigated heat exposure and heat-related symptoms which sugarcane workers (90 sugarcane cutters and 93 factory workers) experienced during a harvesting season in Thailand. During the hottest month of harvesting season, wet bulb globe temperature was collected in the work environment, and workloads observed, to assess heat stress. Urine samples for dehydration test, blood pressure, heart rate, and body temperature were measured pre- and post-shift to measure heat strain. Fluid intake and heat-related symptoms which subjects had experienced during the harvesting season were gathered via interviews at the end of the season. From the results, sugarcane cutters showed high risk for heat stress and strain, unlike factory workers who had low risk based on the American Conference of Governmental Industrial Hygiene (ACGIH) threshold limit values (TLVs) for heat stress. Dehydration was observed among sugarcane cutters and significant physiological changes including heart rate, body temperature, and systolic blood pressure occurred across the work shift. Significantly more sugarcane cutters reported experiencing heat-related symptoms including weakness/fatigue, heavy sweating, headache, rash, muscle cramp, dry mouth, dizziness, fever, dry/cracking skin, and swelling, compared to sugarcane factory workers. We conclude that the heat stress experienced by sugarcane cutters working in extremely hot environments, with high workloads, is associated with acute health effects. Preventive and control measures for heat stress are needed to reduce the risk of heat strain.

Working Conditions and Urinalysis Dipstick Testing among Female Rice Farmers: A Preliminary Cross-Sectional Study

“…This indicates that the urine was normal and slightly acidic. This is in accord with findings from studies of Thai sugarcane workers, who tended to have acidic urine (pH 5-6) [31]. We also tested whether age and work experience were associated with urine pH level and specific gravity.…”

Determinants of Hypertension amongst Rice Farmers in West Java, Indonesia

“…A study on sugarcane cutters with an increased risk of heat stress found a significant increase in heart rate, temperature, and blood pressure (SBP) occurred across the work shift [32]. However, another study found a significant increase in heat rate, but a decrease of SBP and DBP across 4 h shifts in sugarcane cutter in El Salvador [33].…”

Risk factors associated with heat-related illness among sugarcane farmers in Thailand

“…Most of those affected were farmers because these workers are exposed to heat in full sunlight and have a heavy workload throughout their working lifetime 14 ) . Likewise, a previous study among Thai sugarcane cutters demonstrated that working in the extreme heat with a heavy workload is associated with heat-related illness symptoms 15 ) .…”

“…All participants were asked whether they had experienced each symptom during the summer at work; responses were “never”, “sometimes”, or “regularly” (at least once per week). For data analysis, “sometimes” and “regularly” were grouped into one variable, denoted “ever” 15 ) . The third part of the questionnaire addressed occupational factors, including heat exposure duration per day, work clothing ensembles, and fluid intake per day.…”

“…Most of those affected were farmers because these workers are exposed to heat in full sunlight and have a heavy workload throughout their working lifetime 14) . Likewise, a previous study among Thai sugarcane cutters demonstrated that working in the extreme heat with a heavy workload is associated with heat-related illness symptoms 15) . Sugarcane farmers are an essential workforce for the economy of Thailand, the fourth largest sugarcane producer globally, accounting for 8.10% of the world's sugar production.…”