Notley SR, Poirier MP, Sigal RJ, et al. – Exercising in the heat can raise the risk of health complications—particularly among middle-aged and older adults with impaired whole-body heat loss (WBHL) vs young adults. And this risk may be even higher among patients with type 2 diabetes (T2D) due to abnormalities in cutaneous vasodilation and sweating, which can facilitate WBHL. Repeated brief exercise for ≥ 7 days during heat exposure (heat acclimation), however, may decrease this risk by boosting WBHL. Researchers, therefore, assessed whether T2D impairs heat loss in physically active middle-aged and older adults during exercise heat stress and whether heat acclimation could counterbalance any impairment.