Linking changes in heart rate variability to mood changes in daily life

Background: Dynamic changes of heart rate are considered as markers for autonomic nervous system (ANS) balance and potentially mood. Objective markers of mood are especially of interest when monitoring mental health conditions such as bipolar disorder (BD) and borderline personality disorder (BPD). Methods: Ambulatory ECG recordings, actigraphy and mood recordings were collected from 13 BD, 10 BPD and 15 healthy participants. A total of246 5-minute segments of ECG with a corresponding mood entry and actigraphy recording were collected. Heart rate variability (HRV) measures were calculated for each segment. Results: Significant effects were found for changes in positive mood on changes in HRV for BD participants (R²=0.076, p=0.009) for mean R-R interval (mRR) and (R²=0.061, p=0.026) for high frequency (HF) frequency power. Similar effects were found for BPD participants for negative mood on mRR (R²=0.126, p=0.014) and on negative mood and HF (R²=0.81, p=0.049). Conclusions: Objective measures, such as HRV, which are shown to be linked to changes in mood could allow better understanding of the relationship between mood and cardiovascular behaviour in mental health disorders. In the future, such metrics could help management of these conditions through adjustments in treatments.