Heart rate variability assessment in Japanese workers recovered from depressive disorders resulting from job stress: measurements in the workplace.

PURPOSE: The purpose of this study is to clarify workers' autonomic nerve balance after long-term sick leave due to depressive disorders resulting from job stress compared with healthy workers.
METHODS: The participants were 28 Japanese male workers recovered from depressive disorders and 75 healthy male workers. For each participant, the lifestyle and the fatigue within 1 month were assessed by a checklist. Heart rate variability (HRV) was measured at the workplace by acceleration plethysmography (APG). HRV was assessed by the coefficient of variation of rate intervals (CV), the spectral components in the high- and low-frequency areas represented by the normalized HF and LF (nHF and nLF), and the ratio of LF to HF components (LF/HF).
RESULTS: There was no significant difference in individual lifestyle and fatigue symptoms between the recovered and the healthy workers. The former workers showed significantly lower CV, higher nLF and log(10)LF/HF, and lower nHF that represent the predominance of sympathetic activity in comparison with the healthy workers. Moreover, the recovered workers who discontinued medications indicated significantly higher nLF and log(10)LF/HF, and lower nHF compared to the recovered workers who continued their medications.
CONCLUSIONS: Recovered workers in the workplace tended to show the depressive HRV feature that is the dominant sympathetic activity compared with the healthy workers. They might still be showing job stress that was not detected by the checklist. HRV analyses by APG in addition to questionnaire has the potential to become an effective approach for assessing workers' job stress to prevent repeated absences.