Shivering, but not adipose tissue thermogenesis, increases as a function of mean skin temperature in cold-exposed men and women.

Abstract

Skin cooling results in the activation of heat-generating mechanisms to counteract heat lost to the environment. Here, we aim to understand the extent to which variations in cold-stimulated heat production may be driven by differences in the contribution of shivering and non-shivering thermogenesis (NST) and the interaction with biological sex. Using a novel mean skin temperature clamping technique in healthy men and women, our data show that cold-stimulated heat production rises with increasing shivering and myocardial oxidative metabolism in a skin temperature-dependent fashion. Shivering and myocardial thermogenesis were also moderately associated. By contrast, adipose tissue NST did not increase in a linear manner to reductions in skin temperature. Men and women displayed similar thermoregulatory responses, although women presented more pronounced shivering through a greater recruitment of lower-body muscles and a greater number of motor units recruited. Thus, shivering contributes proportionally to cold-induced thermogenesis, whereas adipose tissue thermogenesis displays an all-or-none response.