Zhang K, Sun M, Werner P, Kovera A J, Albu J, Pi-Sunyer F X, Boozer C N
Institute of Human Nutrition, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, USA.
Int J Obes Relat Metab Disord. 2002 Mar;26(3):376-83. doi: 10.1038/sj.ijo.0801922.
To determine whether patterns of sleeping metabolic rate (SMR) are altered in obesity. Specifically to determine the relationship between changes in SMR and body weight, body mass index (BMI, kg/m(2)), and fat-free mass (FFM); and to compare resting metabolic rate (RMR) with SMR during different periods of sleep.
Eighteen healthy, pre-menopausal, obese (BMI >30, n=9) and non-obese (BMI <30, n=9), female subjects (six Caucasians and 12 African-Americans), with an average age of 36 y (range 22-45).
Total energy expenditure (TEE or 24 h EE), metabolic rate (MR), SMR (minimum, average and maximum) and resting metabolic rate (RMR) or resting energy expenditure (REE) measured by human respiratory chamber, and external mechanical work measured by a force platform within the respiratory chamber. Physical activity index (PAL) was derived as TEE/REE. Body composition was determined by dual-energy X-ray absorptiometry (DXA).
SMR decreased continuously during sleep and reached its lowest point just before the subject was awakened in the morning by the research staff. Although averages for RMR and SMR were similar, RMR was lower than SMR at the beginning of the sleeping period and higher than SMR in the morning hours. The rate of decrease in SMR was faster with increasing body weight (-0.829, P<0.0001), BMI (correlation factor -0.896, P<0.0001) and FFM (-0.798, P=0.001). The relationship between the slope of SMR decrease and BMI (y=-5 x 10(-6)x(2)+0.0002x-0.0028) is highly significant, with a P-value of <0.0001 and r(2) value of 0.9622.
The rate of decline in metabolic rate during sleep is directly related to body weight, BMI and FFM. Average SMR tends to be lower than RMR in obese subjects and higher than RMR in non-obese subjects.
确定肥胖者睡眠代谢率（SMR）模式是否改变。具体而言，确定SMR变化与体重、体重指数（BMI，kg/m²）和去脂体重（FFM）之间的关系；并比较不同睡眠阶段的静息代谢率（RMR）和SMR。
18名健康的绝经前女性受试者，其中肥胖者（BMI>30，n = 9）和非肥胖者（BMI<30，n = 9）各9名（6名白种人和12名非裔美国人），平均年龄36岁（范围22 - 45岁）。
通过人体呼吸舱测量总能量消耗（TEE或24小时能量消耗）、代谢率（MR）、SMR（最小值、平均值和最大值）以及静息代谢率（RMR）或静息能量消耗（REE），并通过呼吸舱内的力平台测量外部机械功。身体活动指数（PAL）通过TEE/REE得出。通过双能X线吸收法（DXA）测定身体成分。
睡眠期间SMR持续下降，在研究人员早晨唤醒受试者之前达到最低点。虽然RMR和SMR的平均值相似，但睡眠初期RMR低于SMR，早晨时段RMR高于SMR。随着体重增加（-0.829，P<0.0001）、BMI增加（相关系数-0.896，P<0.0001）和FFM增加（-0.798，P = 0.001），SMR下降速度更快。SMR下降斜率与BMI之间的关系（y = -5×10⁻⁶x² + 0.0002x - 0.0028）高度显著，P值<0.0001，r²值为0.9622。
睡眠期间代谢率下降速率与体重、BMI和FFM直接相关。肥胖受试者的平均SMR往往低于RMR，非肥胖受试者的平均SMR往往高于RMR。
