Heart Rate Variability, Cortisol and Attention Focus During Shamatha Quiescence Meditation

Abstract

Cardiac vagal tone can be seen as a stable marker for the ability to sustain attention and regulate emotion, two factors associated with the quality of meditation. In this study, heart rate variability (HRV) has been monitored in different forms of Shamatha quiescence meditation: three breath meditations, Settling the Mind in its natural state, Awareness of Awareness, Loving-kindness and Tonglen. Establish and test a practical means of monitoring neurobiological effects of meditation. Over 6 weeks, two experimental groups practiced Shamatha meditation on a daily basis (n = 20). HRV patterns and cortisol tests were monitored at three measuring points during these weeks, and an attention focus test was performed at the start and after 6 weeks. Six weeks of regular practice in Shamatha meditation were associated with HRV indices suggesting improvements in the homeostatic regulation of the autonomic nervous system (ANS) in 85% of the HRV recordings (tachogram and frequency specter) of all 20 subjects. Further, a substantial decrease in cortisol levels was also noted. The attention focus test showed a significant increase of 18.7% in sustained attention, moving from medium to high attention focus, with a significant result of t(20) = − 8.764 and p < 0.001. Participants reported positive subjective changes in attention focus, sense of happiness and calmness and increased abilities in emotional regulation and attunement. Six weeks of regular practice in Shamatha meditation contributes to a substantial increase of attention focus and a decrease in stress levels evidenced in changes in diurnal cortisol measures. HRV biofeedback shows that the sympathetic nervous system is counterbalanced by increased vagal tone, and autonomic balance is enhanced by all Shamatha meditations, not only breath meditations, but also mind meditations: Settling the Mind in its natural state, Awareness of Awareness, Loving-kindness and Tonglen. Although these results are promising, further research is recommended with HRV biofeedback instruments to report statistical analysis and to understand unique HRV patterns in Shamatha mind meditation.