Women exhibit different thermoregulatory responses to meal and cold stimuli compared to men independently of energy expenditure and body composition.

BACKGROUND & AIMS: Meal-induced thermogenesis (MIT) and cold-induced thermogenesis (CIT) are components of adaptive thermogenesis, both potential contributors to energy balance and body composition. This study examined sex differences in thermogenic and thermoregulatory responses to a meal and to cold exposure, and evaluated their associations with body composition in young adults. METHODS: Sixty-three adults (68% women) with valid MIT data, and forty-eight (63% women) with valid CIT data were included. Energy expenditure (EE) was assessed via indirect calorimetry during standardized meal and cold exposure tests. Body composition was determined by dual-energy X-ray absorptiometry. Skin temperature was continuously monitored using wireless sensors. RESULTS: EE increased after both meal intake and cold exposure (both P < 0.01) in men and women. During MIT, women exhibited higher mean and proximal skin temperatures than men (P < 0.04). Similar differences were observed during CIT (P < 0.03). MIT and CIT were not associated with body composition parameters (all P > 0.05). CIT was positively associated with supraclavicular skin temperature (R2 = 0.21, β = 0.32, P = 0.05), while no associations were observed for MIT and skin temperature (all P > 0.10). CONCLUSION: Despite similar EE during MIT and CIT, women show higher skin temperatures during both tests, suggesting greater thermoregulatory efficiency. Supraclavicular skin temperature may serve as a non-invasive physiological indicator of CIT.