Temperature regulation during exercise in the heat: Insights for the aging athlete

Abstract

Objective: The purpose of this review is to evaluate the currently-available literature regarding the impact of both primary aging and age-related fitness on thermoregulatory function during exercise in the heat. In so doing, we aim to (1) characterize the influence of fitness in mitigating age-related declines in thermoregulation, (2) address the limitations of prior experimental approaches for investigating agerelated thermoregulatory impairments, (3) examine to what extent aerobic fitness can be maintained in the aging athlete, and (4) begin to address the specific environmental conditions in which age-related impairments in thermoregulatory function may place highly active older adults at increased risk for heat-related illness and injury and/or limited performance. Design: Mini-review. Methods: Review and synthesis of available information. Results: The earth's climate is warming, accompanied by a consequently greater frequency and severity of extreme heat events. At the same time, lifespan is increasing and people of all ages are staying increasingly active. Age-related impairments in thermoregulatory function are well-documented, leading to increased heat-related health risks and reduced exercise/athletic performance for older adults in hot environmental conditions. High aerobic fitness improves body temperature regulation during exercise via augmented sweating and improved cardiovascular function, including cardiac output and skin blood flow, in humans of all ages. Conclusions: The masters athlete is better suited for exercise/heat-stress compared to his or her less fit peers. However, while age and thermoregulation in general has been studied extensively, research on the most fit older adults, including highly competitive athletes, is generally lacking.

Biomarkers of aging

“…With age, impaired secretion of sweat glands along with reduced vasodilation of dermal arterioles and the loss of subcutaneous fat led to thermoregulation disorders (Ding et al, 2021b;Lazarus et al, 2019). Repair processes of collagen remodeling, cell proliferation, and wound metabolism in the elderly were shown to be delayed (Kenney et al, 2021;Mistry et al, 2021). Furthermore, a more pronounced inflammatory phenotype has been uncovered in aged skin wounds, featured by the persistence of neutrophils and a higher abundance of inflammatory macrophage subsets compared to younger counterparts (Kenney et al, 2021;Vu et al, 2022).…”

“…Repair processes of collagen remodeling, cell proliferation, and wound metabolism in the elderly were shown to be delayed (Kenney et al, 2021;Mistry et al, 2021). Furthermore, a more pronounced inflammatory phenotype has been uncovered in aged skin wounds, featured by the persistence of neutrophils and a higher abundance of inflammatory macrophage subsets compared to younger counterparts (Kenney et al, 2021;Vu et al, 2022). Recent studies have also revealed an increase in immuno-suppressive activity in the aging process of the skin (Salminen, 2020;Salminen et al, 2022).…”

Humidity’s Role in Heat-Related Health Outcomes: A Heated Debate

“…Progressive impairments in the human sweating response occur naturally with aging owing to reduced peripheral sensitivity to acetylcholine, the neurotransmitter predominantly responsible for eccrine sweating, and atrophy of the sweat glands. 93 Above the age of 60 y, thermoregulatory sweating can decline by up to 25%, although these impairments can be delayed by regular aerobic training. 94 Anticholinergic medications, such as many antidepressants and psychotropic medicines, also theoretically attenuate sweating, 95 as do other medications that alter peripheral vasodilation, such as anti-adrenergics and beta-blockers.…”

Trends in Weather Conditions and Performance by Age Groups Over the History of the Berlin Marathon

“…Humidity has been suggested as a factor of heat dissipation, and consequently, an increase of humidity would affect negatively the balance between heat production ad dissipation ( Bouscaren et al, 2019 ). In addition, the thermoregulation has been well-documented to be impaired with aging reducing sport performance for master athletes especially in hot environmental conditions ( Kenney et al, 2020 ). These age-related differences in thermoregulation might be attributed to differences in performance related characteristics (e.g., physical fitness and body composition) ( Kenney and Munce, 2003 ).…”