Estimation Method for Biorhythm by Using Electrocardiogram During Sleep

Abstract

The conditioning for athletes depends on their self-management or the experiences of their coaches. We focused on circadian rhythm which is related to physical and mental condition. The conventional method for estimating circadian rhythm is not suitable for daily measurement because of the measurement for more than 24 hours and restricting exercise in the daytime. Hence, we developed an algorithm for estimating circadian rhythm by using Electrocardiogram (ECG) during sleep. We evaluated the effectivity of this algorithm as compared with circadian rhythm measured by core temperature as the reference data. Both were related to strong positive correlation in data without first-night effect. Further the average of the error time (difference in the lowest time calculated by deep forehead temperature and ECG) was only 20 minutes. As the results, we succeeded in estimation of the time and heart rate value to reach the lowest point in circadian rhythm in normal sleep.