Calton Emily K, Soares Mario J, James Anthony P, Woodman Richard J
Health Promotion & Disease Prevention, School of Public Health, CHIRI-Metabolic Health, Curtin University, Perth, Western Australia, Australia.
Faculty of Medicine, Flinders Centre for Epidemiology and Biostatistics School of Medicine, Nursing and Health Sciences, Flinders University of South Australia, Adelaide, South Australia, 5001.
Am J Hum Biol. 2016 Sep 10;28(5):699-704. doi: 10.1002/ajhb.22853. Epub 2016 Mar 23.
To determine the acute effect of a mild cold exposure on thermoregulatory thermogenesis and the role of circulating irisin in the process.
We studied 22 adults (9 males, 13 females) aged 57.7 ± 10.07 years and body mass index 27.8 ± 4.52 kg/m(2) . Participants experienced a 90-min exposure to 20°C and 25°C in a randomized cross-over design. Resting metabolic rate (RMR), forearm to finger-tip gradient (FFG), blood pressure (BP), in-the-ear temperature (IET), and fasting bloods were measured on each occasion.
There were significant increases in FFG [mean ± SD: +3.8 ± 3.0°C, P < 0.001], systolic blood pressure (SBP) [+8 ± 13 mm Hg, P = 0.015], and diastolic blood pressure (DBP) [+4 ± 6 mm Hg, P = 0.005] and decreases in IET [-0.24 ± 0.29°C, P = 0.001]. Overall, RMR [+190 ± 570 kJ/d, P = 0.135], irisin, glucose or insulin did not differ between temperatures. There were no significant between-gender differences, but males significantly increased SBP (+12 ± 16, P = 0.02) and DBP (+6 ± 7, P = 0.02) with decreases in heart rate (-4 ± 3, P = 0.002), while females did not. Moreover men had approximately 50% higher thermogenic response while women had approximately 25% greater vasoconstrictor response. Adjusted for age, gender, insulin sensitivity, and body composition, fold changes in irisin were inversely related to respiratory quotient (r= -0.54, P = 0.048), while IET was related to FFG (r= -0.55, P = 0.043).
Mild cold exposure increased vasoconstriction with a drop in IET and these were related. Greater irisin was related to a greater fasting fat oxidation in the absence of shivering. A potential gender bias in thermoregulation was noted. Am. J. Hum. Biol. 28:699-704, 2016. © 2016 Wiley Periodicals, Inc.
确定轻度冷暴露对体温调节性产热的急性影响以及循环鸢尾素在此过程中的作用。
我们研究了22名成年人（9名男性，13名女性），年龄57.7±10.07岁，体重指数27.8±4.52kg/m²。参与者采用随机交叉设计，在20°C和25°C环境中暴露90分钟。每次均测量静息代谢率（RMR）、前臂至指尖温度梯度（FFG）、血压（BP）、耳内温度（IET）和空腹血样。
FFG显著升高[平均值±标准差：+3.8±3.0°C，P<0.001]，收缩压（SBP）升高[+8±13mmHg，P=0.015]，舒张压（DBP）升高[+4±6mmHg，P=0.005]，IET降低[-0.24±0.29°C，P=0.001]。总体而言，RMR[+190±570kJ/d，P=0.135]、鸢尾素、葡萄糖或胰岛素在不同温度之间无差异。性别之间无显著差异，但男性SBP显著升高（+12±16，P=0.02）和DBP显著升高（+6±7，P=0.02），心率降低（-4±3，P=0.002），而女性则无此变化。此外，男性的产热反应约高50%，而女性的血管收缩反应约高25%。校正年龄、性别、胰岛素敏感性和身体成分后，鸢尾素的倍数变化与呼吸商呈负相关（r=-0.54，P=0.048），而IET与FFG相关（r=-0.55，P=0.043）。
轻度冷暴露会增加血管收缩并导致IET下降，且二者相关。在无寒颤的情况下，较高的鸢尾素与较高的空腹脂肪氧化有关。注意到体温调节中存在潜在的性别差异。《美国人类生物学杂志》28:699 - 704，2016年。©2016威利期刊公司
