Comparison of Heart Rate Variability between Mild and Severe Depression in Menopausal Women with Low Exercise Behavior

[Purpose] Insufficient exercise leads most middle-aged women to have a higher risk of depression arising from menopausal symptoms. We hypothesized that heart rate variability (HRV) would show the adjustment of the autonomic nervous system reflecting degrees of depression in menopausal women with low exercise behaviors, and the aim of this study was to compare HRV between mild and severe depression cases to explore the potential of HRV as a diagnostic tool for depression. [Subjects and Methods] This was a cross-sectional study, and subjects were community-recruited menopausal women with low exercise behaviors. After subjects had completed the Taiwanese depression questionnaire (TDQ), electrocardiographic signals of the subjects with mild and severe depression were recorded for analysis of the HRV variables, and to create receiver operating characteristic curves. [Results] Twentyeight women with mild depression (TDQ score: 11.62 ± 1.81) and 20 women with severe depression (TDQ score: 24.71 ± 1.57) agreed to analysis of their electrocardiographic signals. The between-group comparisons of high frequency (HF), low frequency (LF) and the LF/HF ratio showed statistically significant differences, and provided significant contributions to predicting depression in both groups. The area under the receiver operating characteristic curve for LF was significantly greater than that of HF. [Conclusions] LF and the LF/HF ratio better distinguish between subjects of different severity of depression than HF. This means that observation of the tone of sympathetic activity and the balance of the autonomic nervous system are better at distinguishing the severity of depression.