Elevated Core Temperature in Florida Fernery Workers: Results of a Pilot Study

With expected increases in extreme weather, there may be a greater risk of injury from extreme heat in outdoor worker populations. To plan for future adaptation measures, studies are needed that can characterize workers' physiologic responses to heat in outdoor settings such as agriculture. The objective of this study was to characterize occupational heat exposure, key vulnerability factors (e.g., gender, energy expenditure), and physiologic heat stress response in a sample of fernery workers. Forty-three fernery workers over 86 workdays were examined regarding heat-related illness (HRI) during the summer months of 2012 and 2013. The key outcome measure was whether a participant's body core temperature (T_c) reached or exceeded 38.0°C (100.4ºF; T_c38). Participants' T_c exceeded 38.0°C on 49 (57%) of the workdays, with 30 of 40 participants reaching or exceeding T_c38 on at least one workday. Adjusting for sex, there was a 12% increase in the odds of T_c38 for every 100 kilocalories of energy expended (OR: 1.12; 95% Confidence Interval [CI]: [1.03, 1.21]). Adjusting for energy expenditure, females had 5 times greater odds of T_c38 compared with males (OR: 5.38; 95% CI: [1.03, 18.30]). These findings provide evidence of elevated T_c in Florida fernery workers, indicating an increased risk of occupational HRI, and the need for policy and interventions to address this health risk.