Fatigability is among the factors of discoordination between heart rate variability and physical acceleration during free-moving days in non-older women

Fatigability is related to several diseases as well as the autonomic nervous system. We investigated whether fatigability is associated with the coordination between the physical acceleration (PA) and heart rate variability (HRV) in women. Overall, 95 adult women were divided into non-old (n=50; age: 22–59 years) and old group (n=45; age: ≥ 60 years). HRV and PA data were simultaneously obtained every minute for 24 h. We defined %lag0 as the percent ratio of lag=0 min between HRV and PA in 1 h. Cornell Medical Index was used to determine the degrees of physical and psychological symptoms. In the non-older group in the hour before sleep, the participants with high fatigability scores had significantly lower %lag0 than those with low fatigability %lag0 (p<0.05). Additionally, those with higher fatigability combined with exhaustion in the morning had significantly lower %lag0 than those without exhaustion in the hour before sleep (p<0.05) but not in the hour after waking up. These results suggest that fatigability in non-older women was associated with the discoordination between HRV and PA in the hour before sleep. Additionally, exhaustion in the morning may be related to the discoordination of HRV and PA the previous night.