Cooling during heat waves is essential for protecting health
Extreme heat poses substantial health risks, with older adults, people with chronic illnesses, and those unable to limit exposure most at risk (unhoused people, those without air-conditioning, workers).1
Limiting physical exertion and maintaining hydration mitigates excessive heat strain
Physical exertion in hot environments increases internal heat production. When exertion is unavoidable, 15 to 45 minutes of rest in shaded or cool spaces should be scheduled per hour, depending on work intensity.2 Supplemental cooling practices should be employed for more intense work. People should drink water, aiming to maintain stable body weight (avoiding sugary or caffeinated beverages) to prevent dehydration and support body temperature regulation.
Cool spaces provide thermal and cardiovascular relief, but the benefits are temporary
Although public cool spaces offer temporary relief during heat waves, their benefit is short lived, requiring additional measures to mitigate heat-related risks when people return to hotter environments.3 Access to cool spaces is especially crucial for populations who may lack adequate cooling at home or work.
Low-cost cooling strategies can provide relief, but their efficacy is limited
Electric fans can help cool the body by facilitating sweat evaporation, but become less effective for older adults at air temperatures higher than 33°C and can worsen heat strain above 40°C.4,5 Misting skin with cool water can enhance the cooling effect of fans at temperatures of 38°C or lower,5 and immersing limbs in cool water and applying cold towels on the neck may provide some relief at temperatures of 36°C or lower.6
Although highly effective, air-conditioning is not universally accessible
Cooling indoor air is the most effective way to prevent heat-related death. Maintaining indoor temperatures at 26°C or lower is recommended,1 but air-conditioning remains inaccessible for many low-income households and workplaces. Expanding access, and lowering costs through subsidies,7 rebates, and complementary cooling strategies, is essential to ensure equitable protection for those at risk.1,5
Footnotes
Competing interests: None declared.
This article has been peer reviewed.
References
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