The simple practice of sitting still or steady walking bring you to a firmer place in yourself, your still centre. This is because “mind” is a mixture of heart and brain functions, in which the heart is predominantly involved with the steady receptivity we call mindfulness and clear comprehension. The heart is not just a metaphor for emotions and perceptions. So when we “tune in” to a still body or to the rhythm of breathing, the message we receive is that things are fine and the brain quietens down. This is the often overlooked function of the heart: it is a major contributor to direct experience (rather than figured out, learned or abstract knowledge).
Ajahn Sucitto, Meditation, A Way of Awakening