Stupfel M, Gourlet V, Court L
Gerontology. 1986;32(2):81-90. doi: 10.1159/000212770.
Continuous monitoring of emitted carbon dioxide (VCO2) was taken as an index of respiratory exchanges in male Sprague-Dawley rats of different ages (31-814 days) submitted to a light (100 lx)-dark (LD) 06.00-18.00 h alternation at a temperature of 20 degrees C and with food and water ad libitum. In grouped 82- and 426-day-old rats harmonic and spectral analyses show that aging decreases the amplitudes of the circadian (tau = 24 h) respiratory rhythms, decreases the amplitudes and modifies the phases of the ultradian respiratory rhythms of mean and great (10 min less than tau less than 24 h) periods. Under the environmental conditions of the experiments, the techniques utilized show no statistically significant changes with aging for the circadian rhythms and only small changes in the ultradian respiratory frequencies.
在温度为20摄氏度、光照（100勒克斯）-黑暗（LD）于06:00-18:00交替且自由获取食物和水的条件下，对不同年龄（31-814天）的雄性斯普拉格-道利大鼠呼出二氧化碳（VCO2）进行连续监测，以此作为呼吸交换指标。在对82日龄和426日龄大鼠分组研究中，谐波和频谱分析表明，衰老会降低昼夜节律（τ = 24小时）呼吸节律的振幅，降低平均周期和长周期（10分钟＜τ＜24小时）超日呼吸节律的振幅并改变其相位。在实验环境条件下，所采用的技术显示，昼夜节律随衰老无统计学显著变化，超日呼吸频率仅有微小变化。
