Innovative Cooling Technique: Submerging Forearms in Water Helps Protect Older Adults During Extreme Heat

As global temperatures rise and heatwaves become more frequent, protecting vulnerable populations—especially older adults—has become a public health priority. Researchers from Pennsylvania State University have uncovered a simple, low-cost method to help older individuals manage heat stress: submerging the hands and forearms in room-temperature water.

This method, tested during controlled heat stress experiments, involves immersing hands and forearms up to the elbows in water at about 68°F (20°C). The study found that this action can significantly reduce core body temperature—by approximately half a degree Fahrenheit—and lower heart rates, thereby decreasing cardiovascular strain. These effects are crucial because, in extreme heat, an increase in core temperature can lead to dangerous health outcomes such as heat exhaustion and heat stroke.

The research, led by Dr. Rachel Cottle, involved 12 healthy adults over the age of 65. Participants were exposed to two hours of heat at 93°F with high humidity, simulating conditions that typically cause a steady rise in core temperature among older adults. During half of the trials, participants immersed their hands and forearms in water for ten minutes after the first hour and again at 80 minutes. Results showed that this cooling strategy effectively moderated temperature and heart rate increases.

This simple intervention offers a practical solution, especially during power outages or in situations where air conditioning or electric fans are unavailable. It mimics how filling a sink with tap water once and reusing it can help maintain a cooler body temperature. While not a substitute for seeking cooler environments, forearm immersion can extend the safe period before heat-related health risks become serious.

Experts highlight that staying hydrated, seeking air-conditioned spaces, and reducing physical exertion remain the most effective methods for heat protection. Nonetheless, in scenarios where cooling options are limited, hand and forearm immersion provides a helpful, accessible method to safeguard older adults from the adverse effects of extreme heat.

This research underscores the importance of simple, affordable strategies in protecting vulnerable populations as climate-related heat events increase worldwide.