Evaluating Heat Acclimation by Warm Water Immersion to Reduce Heat and Cardiovascular Stress in Older Women During Indoor Overheating

What this Trial Is About

Researchers are studying ways to help older women become more resilient to heat during indoor overheating events, which are expected to increase due to global warming. The study focuses on women aged 65 to 85, who are more vulnerable to heat stress and related health risks, especially those without access to air conditioning or reliable electricity. Previous findings showed that passive heat exposure like warm-water immersion may improve the body's ability to lose heat and reduce strain, but this has not yet been confirmed in realistic indoor heat conditions for older women. Participants will undergo a 7-day heat acclimation protocol involving warm-water immersion up to shoulder level in approximately 40°C water until their core temperature reaches about 38.5°C and is maintained for 60 minutes. Before and after this protocol, they will be exposed to a 10-hour indoor heat session at 36°C and 45% humidity, simulating extreme indoor heat conditions. During this exposure, participants will mostly remain seated with brief hourly stretching breaks. During the study, researchers will monitor core body temperature, heart rate, blood pressure, cognitive function, balance, and mood among other measures to assess heat and cardiovascular strain. They will also track fluid loss, thirst, thermal comfort, and symptoms related to heat exposure. These evaluations will help determine whether the warm-water immersion protocol reduces the physical and mental stress caused by prolonged heat exposure. The total study duration includes the 7-day immersion period and assessments before and after the heat exposures.

Enhancing Heat Resiliency in Older Adults During Indoor Overheating Via Heat Acclimation by Warm Water Immersion