Physiological factors characterizing heat-vulnerable older adults: A narrative review

• Published in: Environment international Vol. 144; p. 105909
• Main Authors: Meade, Robert D., Akerman, Ashley P., Notley, Sean R., McGinn, Ryan, Poirier, Paul, Gosselin, Pierre, Kenny, Glen P.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.11.2020; Elsevier
• Subjects: Aged; Aging; Cardiovascular; Chronic disease; Climate Change; Diabetes Mellitus, Type 2; Extreme Heat; Heat stress; Heatwaves; Hot Temperature; Humans; Morbidity; Thermoregulation; Climate change; Heatwaves; Chronic disease; Cardiovascular; Aging; Thermoregulation; Heat stress
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2020.105909

•Heatwaves are associated with stark elevations in morbidity and mortality.•Older adults are at particular risk of multiple pathophysiological conditions.•Aging and disease elicit impaired physiological responses to heat stress.•These impairments can lead to acute and chronic injury in sensitive bodily systems.•Research is needed to better delineate health impacts of heatwaves in older adults. More frequent and intense periods of extreme heat (heatwaves) represent the most direct challenge to human health posed by climate change. Older adults are particularly vulnerable, especially those with common age-associated chronic health conditions (e.g., cardiovascular disease, hypertension, obesity, type 2 diabetes, chronic kidney disease). In parallel, the global population is aging and age-associated disease rates are on the rise. Impairments in the physiological responses tasked with maintaining homeostasis during heat exposure have long been thought to contribute to increased risk of health disorders in older adults during heatwaves. As such, a comprehensive overview of the provisional links between age-related physiological dysfunction and elevated risk of heat-related injury in older adults would be of great value to healthcare officials and policy makers concerned with protecting heat-vulnerable sectors of the population from the adverse health impacts of heatwaves. In this narrative review, we therefore summarize our current understanding of the physiological mechanisms by which aging impairs the regulation of body temperature, hemodynamic stability and hydration status. We then examine how these impairments may contribute to acute pathophysiological events common during heatwaves (e.g., heatstroke, major adverse cardiovascular events, acute kidney injury) and discuss how age-associated chronic health conditions may exacerbate those impairments. Finally, we briefly consider the importance of physiological research in the development of climate-health programs aimed at protecting heat-vulnerable individuals.