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Association between haemoglobin A 1c and whole‐body heat loss during exercise‐heat stress in physically active men with type 2 diabetes

2023; Wiley; Volume: 108; Issue: 3 Linguagem: Inglês

10.1113/ep090915

1469-445X

Nathalie V. Kirby, Robert D. Meade, Martin P. Poirier, Ronald J. Sigal, Pierre Boulay, Glen P. Kenny,

Adipose Tissue and Metabolism

Abstract Type 2 diabetes is associated with a reduced capacity to dissipate heat. It is unknown whether this impairment is related to glycaemic control (indexed by glycated haemoglobin; haemoglobin A 1c ) is unknown. We evaluated the association between haemoglobin A 1c and whole‐body heat loss (via direct calorimetry), body core temperature, and heart rate in 26 physically active men with type 2 diabetes (43–73 years; HbA 1c 5.1–9.1%) during exercise at increasing rates of metabolic heat production (∼150, 200, 250 W m −2 ) in the heat (40°C, ∼17% relative humidity). Haemoglobin A 1c was not associated with whole‐body heat loss ( P = 0.617), nor the increase in core temperature from pre‐exercise ( P = 0.347). However, absolute core temperature and heart rate were elevated ∼0.2°C ( P = 0.014) and ∼6 beats min −1 ( P = 0.049), respectively, with every percentage point increase in haemoglobin A 1c . Thus, while haemoglobin A 1c does not appear to modify diabetes‐related reductions in capacity for heat dissipation, it may still have important implications for physiological strain during exercise‐heat stress.