Heart coherence

Guided breathing at a slow, regular pace of about six cycles per minute (5 s in, 5 s out). This rhythm synchronises breathing with heart-rate fluctuations, raises heart-rate variability (HRV) and strengthens vagal tone. The parasympathetic nervous system takes over, stress reactivity drops and cortisol regulation improves. It is the best-documented stress-regulation tool, best practised a few minutes daily rather than in long, occasional sessions.