Slow breathing improves arterial baroreflex sensitivity and decreases blood pressure in essential hypertension

Sympathetic hyperactivity and parasympathetic withdrawal may cause and sustain hypertension. This autonomic imbalance is in turn related to a reduced or reset arterial baroreflex sensitivity and chemoreflex-induced hyperventilation. Slow breathing at 6 breaths/min increases baroreflex sensitivity and reduces sympathetic activity and chemoreflex activation, suggesting a potentially beneficial effect in hypertension. We tested whether slow breathing was capable of modifying blood pressure in hypertensive and control subjects and improving baroreflex sensitivity. Continuous noninvasive blood pressure, RR interval, respiration, and end-tidal CO 2 (CO 2 -et) were monitored in 20 subjects with essential hypertension (56.4±1.9 years) and in 26 controls (52.3±1.4 years) in sitting position during spontaneous breathing and controlled breathing at slower (6/min) and faster (15/min) breathing rate. Baroreflex sensitivity was measured by autoregressive spectral analysis and “alpha angle” method. Slow breathing decreased systolic and diastolic pressures in hypertensive subjects (from 149.7±3.7 to 141.1±4 mm Hg, P P P P P P 2 and faster breathing rate, suggesting hyperventilation and reduced baroreflex sensitivity ( P