Effects of Beta Blockers on Body Temperature in Older Adults During Extreme Heat Exposure

What this Trial Is About

The trial investigates how the drugs propranolol and metoprolol affect core body temperature in older adults during extreme heat exposure. It aims to understand why adults over 65 have higher rates of heat-related illness and death, especially since beta blockers are commonly prescribed for cardiovascular conditions in this age group. This is important because previous studies in younger people showed beta blockers affect sweating and blood flow, but their impact on older adults in heat is unknown. Participants will experience 3 hours of heat exposure in a chamber set to 41C with 40% humidity. They will receive different sequences of propranolol, metoprolol, and placebo in a randomized, double-blind manner to compare effects on their body temperature and sweat rate. The study involves multiple treatment arms rotating these drugs to assess their influence during simulated heat waves. During the study, researchers will continuously measure internal body temperature, heart rate, and blood pressure while also tracking whole body sweat rate before and after heat exposure by measuring body mass. The trial focuses on healthy adults aged 65 and older who meet specific health criteria. The total observation lasts through the 3-hour heat exposure, with close monitoring of cardiovascular and thermoregulatory responses to understand drug effects in aging individuals.

Aging, Beta Blockers, and Thermoregulatory Responses