Low-Energy Cooling Strategies to Mitigate Thermal Strain of Older Adults Exposed to Very Hot-Dry Heat

Authors

Isa A. Farooqi, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital DallasFollow
Zachary J. McKenna, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital DallasFollow
Whitley C. Atkins, University of New Mexico, Department of Health, Exercise & Sports ScienceFollow
Elizabeth A. Gideon, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital DallasFollow
Craig G. Crandall, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, and University of Texas Southwestern Medical Center, Dallas, TXFollow

Abstract

Extreme heat causes morbidity and mortality, particularly among older adults. Although air conditioning can mitigate heat strain, it may be inaccessible due to limited resources, high costs, or power outages. Consequently, cooling strategies other than air-conditioning are needed to mitigate excessive elevations in core temperature and cardiovascular strain in this population. While electric fans offer a low-cost and widely available intervention, their effectiveness in very hot conditions is minimized due to potential increases in heat gain and dehydration. In contrast, skin wetting is a promising low-cost and energy-free cooling strategy that enhances evaporative heat loss. PURPOSE: We tested the hypotheses that skin wetting via water spray attenuates, whereas fans increase, elevations in core temperature and the accompanying cardiovascular strain in older adults exposed to very hot-dry heat with accompanying activities of daily living. METHODS: In a randomized order, 20 older adults (73±5 years; 10 Females) were exposed to 3-hours of ambient heating reflective of the peak environmental conditions during the 2018 Los Angeles heat wave (47ºC, 15% relative humidity) with: a) whole-body skin-wetting every 10 min via water spray, b) continuous electric fan exposure (~2 m/sec), and c) without a cooling intervention (control). To simulate activities of daily living, participants performed six, 5-minute periods of light exercise (~3 METS) dispersed across the heat exposure. Participants consumed 3 mL/kg/hr of tap-temperature water to offset dehydration. We assessed core and skin temperatures, whole-body sweat rate, heart rate, and rate pressure product (heart rate x systolic blood pressure). We compared data using mixed-effects models with a main effect of cooling, and post hoc Dunnett tests to compare against control. RESULTS:: Compared to control, water spray reduced the increase in core temperature by -0.24 °C [95% CI: -0.41 to -0.07; p=.005], ending skin temperature by -2.1°C [95% CI: -2.7 to -1.6; pCONCLUSION:These data demonstrate that water spray attenuates, while an electric fan exacerbates, core temperature and the accompanying cardiovascular strain in older adults exposed to very hot and dry conditions.

Recommended Citation

Farooqi, Isa A.; McKenna, Zachary J.; Atkins, Whitley C.; Gideon, Elizabeth A.; and Crandall, Craig G. (2025) "Low-Energy Cooling Strategies to Mitigate Thermal Strain of Older Adults Exposed to Very Hot-Dry Heat," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 17, Article 43.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss17/43