Straat, Maaike EMartinez-Tellez, BorjaSardjoe Mishre, AashleyVerkleij, Magdalena M AKemmeren, MirjamPelsma, Iris C MAlcantara, Juan M AMendez-Gutierrez, AndreaKooijman, SanderBoon, Mariëtte RRensen, Patrick C N2023-05-032023-05-032022-02-18Straat ME, Martinez-Tellez B, Sardjoe Mishre A, Verkleij MMA, Kemmeren M, Pelsma ICM, et al. Cold-Induced Thermogenesis Shows a Diurnal Variation That Unfolds Differently in Males and Females. J Clin Endocrinol Metab. 2022 May 17;107(6):1626-1635.http://hdl.handle.net/10668/20392Cold exposure mobilizes lipids to feed thermogenic processes in organs, including brown adipose tissue (BAT). In rodents, BAT metabolic activity exhibits a diurnal rhythm, which is highest at the start of the wakeful period. We investigated whether cold-induced thermogenesis displays diurnal variation in humans and differs between the sexes. This randomized crossover study included 24 young and lean male (n = 12) and female (n = 12) participants who underwent 2.5-hour personalized cooling using water-perfused mattresses in the morning (7:45 am) and evening (7:45 pm), with 1 day in between. We measured energy expenditure (EE) and supraclavicular skin temperature in response to cold exposure. In males, cold-induced EE was higher in the morning than in the evening (+54% ± 10% vs +30% ± 7%; P = 0.05) but did not differ between morning and evening in females (+37% ± 9% vs +30% ± 10%; P = 0.42). Only in males, supraclavicular skin temperature upon cold increased more in morning than evening (+0.2 ± 0.1 °C vs -0.2 ± 0.2 °C; P = 0.05). In males, circulating free fatty acid (FFA) levels were increased after morning cold exposure, but not evening (+90% ± 18% vs +9% ± 8%; P  Cold-induced thermogenesis is higher in morning than evening in males; however, lipid metabolism is more modulated in the morning than the evening in females.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/brown adipose tissuecardiometabolic healthcircadian rhythmcold stimulusgender differencesmetabolismAdipose Tissue, BrownCircadian RhythmCold TemperatureCross-Over StudiesEnergy MetabolismFemaleHumansMaleThermogenesisresearch article35176767open accessEstudios cruzadosFemeninoFríoHumanosMasculinoMetabolismo energéticoRitmo circadianoTejido adiposo pardoTermogénesis10.1210/clinem/dgac0941945-7197PMC9113803https://academic.oup.com/jcem/article-pdf/107/6/1626/43740331/dgac094.pdfhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC9113803/pdf