Details

Autor(en) / Beteiligte

• Wolf, S Tony
• Cottle, Rachel M
• Vecellio, Daniel J
• Kenney, W Larry

Titel

Critical environmental limits for young, healthy adults (PSU HEAT Project)

Ist Teil von

• Journal of applied physiology (1985), 2022-02, Vol.132 (2), p.327-333

Ort / Verlag

United States: American Physiological Society

Erscheinungsjahr

2022

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Critical environmental limits are those combinations of ambient temperature and humidity above which heat balance cannot be maintained for a given metabolic heat production, limiting exposure time, and placing individuals at increased risk of heat-related illness. The aim of this study was to establish those limits in young (18-34 yr) healthy adults during low-intensity activity approximating the metabolic demand of activities of daily living. Twenty-five (12 men/13 women) subjects were exposed to progressive heat stress in an environmental chamber at two rates of metabolic heat production chosen to represent minimal activity (MinAct) or light ambulation (LightAmb). Progressive heat stress was performed with either ) constant dry-bulb temperature (T ) and increasing ambient water vapor pressure (P ) (P trials; 36°C, 38°C, or 40°C) or ) constant P and increasing T (T trials; 12, 16, or 20 mmHg). Each subject was tested during MinAct and LightAmb in two to three experimental conditions in random order, for a total of four to six trials per participant. Higher metabolic heat production ( < 0.001) during LightAmb compared with MinAct trials resulted in significantly lower critical environmental limits across all P and T conditions (all < 0.001). These data, presented graphically herein on a psychrometric chart, are the first to define critical environmental limits for young adults during activity resembling those of light household tasks or other activities of daily living and can be used to develop guidelines, policy decisions, and evidence-based alert communications to minimize the deleterious impacts of extreme heat events. Critical environmental limits are those combinations of temperature and humidity above which heat balance cannot be maintained, placing individuals at increased risk of heat-related illness. Those limits have been investigated in young adults during exercise at 30% V̇o , but not during metabolic rates that approximate those of light activities of daily living. Herein, we establish critical environmental limits for young adults at two metabolic rates that reflect activities of daily living and leisurely walking.