A recent study by Penn State researchers demonstrates that submerging hands and forearms in room-temperature water can help protect older adults from heat-related health risks during extreme heat, especially when air conditioning isn't available.

The study involved 12 healthy adults over 65 years old, exposed to heat stress at 93°F with 77% humidity, to simulate conditions where cooling strategies are crucial.

Participants immersed their hands and forearms in 68°F water for 10-minute intervals, which effectively lowered core body temperature and reduced cardiovascular strain.

This water immersion method lowered core body temperature by about half a degree Fahrenheit and significantly decreased heart rate, thereby reducing the risk of heat exhaustion, heat stroke, and cardiac events among vulnerable older adults.

The research underscores that older adults are more susceptible to heat because they have diminished cooling mechanisms, such as less efficient sweating and reduced blood flow to the skin.

With the increasing frequency and severity of heat waves, along with potential power outages affecting air conditioning and fans, simple water immersion techniques could serve as accessible and effective cooling strategies for at-risk populations.

This low-cost intervention is practical during power failures when air conditioning and electric fans are unavailable, as most people still have access to running water.

While electric fans can help, they have limitations during extreme heat and power outages, and excessive heat can sometimes make fans less effective or even increase body temperature.

Experts recommend that, in addition to water immersion, individuals should prioritize reducing heat exposure by moving to cooler environments, staying hydrated, and using fans when possible, as these are primary measures.

The study, published in Experimental Physiology in 2025 with contributions from Penn State and University of Michigan researchers, highlights the importance of community awareness and precautions to protect vulnerable populations during heatwaves.

This simple, low-cost cooling method could extend the safe time window during extreme heat and power outages, helping to prevent heat-related fatalities among older adults.