Grant: Project Grant

Canada is entering unchartered territory as it experiences record high temperatures. However, our understanding of the effects of heat exposure on vulnerable Canadians remains incomplete, limiting our ability to make evidence-based decisions on the best strategies to implement to protect the most vulnerable. Recently, we showed that the body's response to heat is impaired in healthy adults as young as 40 years. This impairment is worse in older adults and in those with even well-controlled diabetes. In these individuals, heat tolerance is reduced as the body is unable to cool itself via the evaporation of sweat, placing them at increased risk of heat-induced illnesses or death. Further, we showed that commonly recommended exposure limits such as the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLV®) to manage the health and safety of individuals during exercise in the heat do not protect middle-aged and older adults from potentially dangerous increases in body heat storage and therefore core temperature. Our project will build on this work by using our air calorimeter (a device to accurately measure the heat dissipated and stored by the body) to assess how the presence of hypertension in older adults, with and without type 2 diabetes, may affect the body's ability to lose heat. Using this gold-standard method we will define the heat thresholds where age- and disease-related impairments in the body's capacity to dissipate can lead to dangerous increases in the amount of heat stored in the body (and therefore core temperature) during simulated exposures to hot weather conditions at rest and during exercise. Our project findings will enable 1) the identification of age- and disease-specific 'high risk' weather and exercise conditions, and 2) the development of short-term (heat advisories, work/exercise exposure limits, etc.) and long-term (heat adaptation strategies) heat protection measures to safeguard health during hot weather.