Relationship between life satisfaction and sympathovagal balance in healthy elderly males at home at night

The aim of this study is to clarify how well-being correlates with autonomic nervous system (sympathovagal) balance in healthy elderly males at home at night awake and resting. The RR-interval and body acceleration of 39 healthy elderly male subjects were recorded with an ambulatory device for 72 hours. The normalized high-frequency (0.15 - 0.4 Hz) power (HFnu) of RR-interval variability (sympathovagal balance index) was calculated from 10 min long data sets that satisfied all of the following conditions: 1) average body acceleration was less than 30 mG, 2) the subject was at home, 3) the subject was awake, and 4) more than 95 percent of the time-series of instantaneous heart rate was within 40 to 160 [bpm]. Subjects recorded their subjective well-being level, including life satisfaction level, on a Visual Analogue Scale (VAS) questionnaire. We investigated the correlation between the subjective well-being level and mean HFnu. A significant negative correlation between life satisfaction level and mean HFnu (r = –0.47, p = 0.004) was observed. This result implies that sympathovagal balance becomes the predominant state of the sympathetic nervous system in healthy elderly males with relatively high life satisfaction while at home at night awake and resting.