Abstract
[Purpose] In a previous paper, we reported that stretching of the triceps surae muscle for 10 minutes induces mental relaxation through an increase in parasympathetic activity, on the basis of spectral analysis of heart rate variability. However, some previous physiological studies of animal mechanoreceptors have indicated that stretching of the skeletal muscle leads to both persistent attenuation of parasympathetic activity and transient weak sympathetic activity. [Subjects] Ten healthy, adult subjects were the subjects. [Methods] In order to elucidate the activity of the autonomic function while the muscle was being stretched, we conducted time-frequency spectral analysis of the heart rate variability, and analysis of the heart rate, and blood pressure. [Results] We found that heart rate increased transiently without an elevation of systolic blood pressure, that HF was attenuated, and that during stretching all of the subjects experienced good feelings. [Conclusion] When comfortis experienced, decrement of parasympathetic nerve action is found during stretching.
