a Graduate School of health Sciences , Kobe University , Kobe , Japan.
b Gaduate School of Health Sciences, Nursing , Kobe University , Kobe , Japan.
Chronobiol Int. 2019 Mar;36(3):374-380. doi: 10.1080/07420528.2018.1550422. Epub 2018 Dec 3.
The notion that sedentary behavior is harmful to human health is widespread. Little is known about the short term influence of sedentary behavior on heart rate (HR) and heart rate variability (HRV) circadian rhythms. Therefore the purpose of the present study was to examine the influence of short term sedentary behavior on the circadian rhythms of HR and HRV using cosine periodic regression analysis. Sixteen healthy young students were included in a randomized crossover study. All subjects underwent 24-h ECG Holter monitoring in two different states of physical activity, an active condition (more than 15,000 steps per day) and a sedentary condition (less than 1,000 steps per day). Hourly mean values were calculated for HR and HRV, and then were evaluated using cosine periodic regression analysis. The circadian rhythm parameters, amplitude, mesor, and acrophase for HR and HRV variables were obtained. As a result, the significance of the circadian rhythm was confirmed for all variables in each condition. The measure of fit R2 value was decreased in sedentary condition. The amplitude of the sedentary condition was significantly smaller than that of the active condition with respect to HR (7.94 ± 1.91 bpm vs. 15.4 ± 3.93 bpm, p < 0.001), natural log of the high frequency measurement (lnHF) (0.38 ± 0.21 ms2 vs. 0.80 ± 0.28 ms2, p < 0.001), and low frequency/high frequency ratio (LF/HF) (0.75 ± 0.54 vs. 1.24 ± 0.69, p = 0.008). We found that sedentary behavior not only significantly lowered the amplitude of HR and HRV variables, but also might have led to weakness of the circadian rhythm of the HR and HRV variables.
久坐行为对人类健康有害的观点已经广为流传。然而，人们对久坐行为对心率（HR）和心率变异性（HRV）昼夜节律的短期影响知之甚少。因此，本研究旨在使用余弦周期回归分析来检验短期久坐行为对 HR 和 HRV 昼夜节律的影响。
研究纳入了 16 名健康的年轻学生，采用随机交叉研究。所有受试者均在两种不同的活动状态下接受 24 小时动态心电图 Holter 监测，活动状态（每天超过 15000 步）和久坐状态（每天少于 1000 步）。计算 HR 和 HRV 的每小时平均值，然后使用余弦周期回归分析进行评估。获得 HR 和 HRV 变量的昼夜节律参数、幅度、中值和高峰时间。
结果，在每种状态下，所有变量的昼夜节律均具有统计学意义。在久坐状态下，拟合度测量 R2 值降低。与活动状态相比，HR（7.94±1.91 bpm 与 15.4±3.93 bpm，p<0.001）、自然对数高频测量值（lnHF）（0.38±0.21 ms2 与 0.80±0.28 ms2，p<0.001）和低频/高频比值（LF/HF）（0.75±0.54 与 1.24±0.69，p=0.008）的幅度在久坐状态下显著较小。
我们发现，久坐行为不仅显著降低了 HR 和 HRV 变量的幅度，而且可能导致 HR 和 HRV 变量昼夜节律的减弱。
