Grant: Project Grant

One direct consequence of climate change is a greater frequency of heat extremes that are associated with health risks worldwide. Striking examples are the 2003 and 2022 European summers that resulted in 70,000 and 60,000 heat-related deaths, respectively. Although there are several populations predisposed to greater health risks during heat extremes, heat-related hospitalisations and deaths occur predominantly amongst older adults. During heat exposure, the physiological responses that serve to maintain a safe core temperature lead to greater health risks. First, an excessive increase in core temperature due to age-related declines in heat loss capacity can lead to injuries such as heatstroke. Second, cardiac work increases during heat exposure which can lead to adverse outcomes such as a heart attack. Third, sweating that is not compensated by adequate fluid intake results in dehydration that can result in electrolyte imbalances and/or kidney injury. Currently, it is unknown why older adults are at greater risk of experiencing such health problems during heat extremes. This project will identify personal characteristics associated with the physiological responses that occur during heat exposure to a hot and humid environment. To achieve this objective, we will expose a varied group of middle-aged to older adults to a hot and humid environment for 4 hours and we will measure their physiological, perceptual and behavioural responses. We will then determine if characteristics such as age, biological sex, health status, and physical activity level are associated with the physiological strain experienced during heat exposure. We will also try to use these characteristics to predict physiological strain during heat exposure. Identifying personal characteristics associated with physiological heat strain will improve our understanding of heat-related health risks in older adults and it could help identify individuals who are at greatest risk.