2022 Volume 60 Issue 6 Pages 175-179
The present investigation aimed to identify the distinguishing effects of spontaneous laughter (SL) and aerobic exercise on autonomic nervous system (ANS) activity to develop a novel technique for indirect SL identification based on heart rate variability (HRV) under daily-living conditions. The subjects of the present investigation were ten healthy young men. The investigation consisted of three 15 min experimental periods, each following a resting period after 5h of daily-living conditions. The three experimental periods included light-intensity aerobic exercise (LAE), moderate-intensity aerobic exercise (MAE), or SL and were randomly distributed across three separate days. To induce SL, the subjects were shown comedy movies. Their ANS activity was monitored throughout the investigation period using continuous heart rate (HR) responses. Total power, low frequency (LF), and high frequency (HF) components were recorded using frequency analysis. LF and HF components were normalized to total power (nHF, nLF), and LF was then divided by HF to obtain a sympathetic activity index (LF/HF) . Instances of SL during the daily-living periods were subjectively identified using laughter intensity scores. Our results revealed a significant correlation between the effects of time and task on HR during the experimental periods (p<0.001) . HR significantly increased during LAE and MAE, but not during SL, compared with that during the resting period (p<0.05) . Temporal effects on ANS were evaluated, and no significant difference was observed between the three conditions. During daily-living conditions, ANS activity differed significantly from baseline (p<0.05) but HR did not. The present investigation revealed that SL induces similar ANS responses but different HR responses compared to aerobic exercise. These findings imply that HR responses via HRV and ANS could provide a novel means of identifying SL in daily-living conditions.
