A modified physiological strain index for workplace‐based assessment of heat strain experienced by agricultural workers
- 4 February 2021
- journal article
- research article
- Published by Wiley in American Journal of Industrial Medicine
- Vol. 64 (4), 258-265
- https://doi.org/10.1002/ajim.23230
Abstract
Background As global temperatures rise, increasing numbers of individuals will work in hot environments. Interventions to protect their health are critical, as are reliable methods to measure the physiological strain experienced from heat exposure. The physiological strain index (PSI) is a measure of heat strain that relies on heart rate and core temperature but is challenging to calculate in a real‐world occupational setting. Methods We modified the PSI for use in field settings where resting temperature and heart rate are not available and used the modified physiological strain index (mPSI) to describe risk factors for high heat strain (mPSI ≥ 7) experienced by agricultural workers in Florida during the summers of 2015 through 2017. mPSI was calculated for 221 workers, yielding 465 days of data. Results A higher heat index (β = 0.185; 95% CI: 0.064, 0.307) and higher levels of physical activity at work (0.033; 95% CI: 0.017, 0.050) were associated with a higher maximum mPSI. More years worked in US agriculture (−0.041; 95% CI: −0.061, −0.020) were protective against a higher maximum mPSI. Out of 23 workdays that a participant experienced a maximum mPSI ≥ 7, 22 were also classified as strained by at least one other measure of high heat strain (core temperature [Tc] >38.5°C, sustained heart rate >(180 − age), and mean heart rate > 115 bpm). Conclusions This study provides critical information on risk factors for elevated heat strain for agricultural workers and suggests a practical approach for using PSI in field‐based settings.Keywords
Funding Information
- National Institute for Occupational Safety and Health (R01OH010657, U54OH011230‐02S1)
- National Institute of Nursing Research (K23NR018485)
This publication has 20 references indexed in Scilit:
- Heat Exposure in Central Florida Fernery Workers: Results of a Feasibility StudyJournal of Agromedicine, 2017
- Heat strain, volume depletion and kidney function in California agricultural workersOccupational and Environmental Medicine, 2017
- Novel Analytic Methods Needed for Real-Time Continuous Core Body Temperature DataWestern Journal of Nursing Research, 2016
- An Evaluation of the Physiological Strain Experienced by Electrical Utility Workers in North AmericaJournal of Occupational and Environmental Hygiene, 2015
- Heat‐related illness in Washington State agriculture and forestry sectorsAmerican Journal of Industrial Medicine, 2014
- The Double Sensor—A non-invasive device to continuously monitor core temperature in humans on earth and in spaceRespiratory Physiology & Neurobiology, 2009
- Research electronic data capture (REDCap)—A metadata-driven methodology and workflow process for providing translational research informatics supportJournal of Biomedical Informatics, 2008
- Thermal Comfort and the Heat Stress IndicesIndustrial Health, 2006
- Perceptual versus physiological heat strain during exercise-heat stressMedicine & Science in Sports & Exercise, 2002
- A physiological strain index to evaluate heat stressAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 1998