Type 2 diabetes does not exacerbate body heat storage in older adults during brief, extreme passive heat exposure. Issue 3 (2nd July 2020)

• Record Type: Journal Article
• Authors: Poirier, Martin P.; Notley, Sean R.; Boulay, Pierre; Sigal, Ronald J.; Friesen, Brian J.; Malcolm, Janine; Flouris, Andreas D.; Kenny, Glen P.
• Is Part Of: Temperature. Volume 7:Issue 3(2020)
• Page Start: 263
• Page End: 269
• Publication Date: 2020-07-02
• Subjects: Aging -- body temperature -- calorimetry -- chronic disease -- climate change -- heat loss; Thermobiology -- Periodicals; Thermotherapy -- Periodicals; Body temperature -- Regulation -- Periodicals; Body temperature -- Regulation; Thermobiology; Thermotherapy; Periodicals; 571.46
• DOI: 10.1080/23328940.2020.1736760
• Languages: English
• ISSNs: 2332-8940

Abstract

ABSTRACT: Aging exacerbates hyperthermia and cardiovascular strain during passive heat exposure, but it remains unclear whether those effects worsen in older adults with type 2 diabetes (T2D). We examined these responses in unacclimatized, physically active, older individuals with (n = 13, mean ± SD age: 60 ± 8 years, HbA1c: 7.0 ± 1.0%) and without (Control, n = 30, 62 ± 6 years) well-controlled T2D during a brief, 3-h passive exposure to extreme heat (44°C, 30% relative humidity). Metabolic heat production, dry heat gain, total heat gain (metabolic heat production + dry heat gain), evaporative heat loss, body heat storage (summation of heat gain/loss), rectal and mean skin temperatures as well as heart rate were measured continuously. No between-group differences were observed for metabolic heat production (T2D vs. Control; 53 ± 5 vs. 55 ± 7 W/m 2 ), dry heat gain (48 ± 9 vs. 47 ± 11 W/m 2 ), total heat gain (101 ± 10 vs. 102 ± 14 W/m 2 ) and evaporative heat loss (83 ± 10 vs. 85 ± 12 W/m 2 ) over the 3 h (all P > 0.05). Consequently, the changes in body heat storage (380 ± 93 vs. 358 ± 172 kJ, P = 0.67) were similar between groups. Moreover, no between-group differences in rectal and mean skin temperatures or heart rate were measured. We conclude that unacclimatized, physically active, older adults with well-controlled T2D do not experience greater hyperthermia and cardiovascular strain compared to their healthy counterparts while resting in extreme heat for a brief, 3-h period.