Slow Breathing Improves Arterial Baroreflex Sensitivity and Decreases Blood Pressure in Essential Hypertension

• Published in: Hypertension (Dallas, Tex. 1979) Vol. 46; no. 4; pp. 714 - 718
• Main Authors: Joseph, Chacko N., Porta, Cesare, Casucci, Gaia, Casiraghi, Nadia, Maffeis, Mara, Rossi, Marco, Bernardi, Luciano
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.10.2005; Hagerstown, MD Lippincott
• Subjects: Arterial hypertension. Arterial hypotension; Arteries - physiopathology; Baroreflex; Biological and medical sciences; Blood and lymphatic vessels; Blood Pressure; Breathing Exercises; Cardiology. Vascular system; Case-Control Studies; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Diastole; Female; Fundamental and applied biological sciences. Psychology; Heart Rate; Hemodynamics. Rheology; Humans; Hypertension - physiopathology; Hypertension - therapy; Male; Medical sciences; Middle Aged; Systole; Vertebrates: cardiovascular system; Human; Hypertension; baroreceptors; Systolic pressure; Chemoreflex; Diastolic pressure; Carbon dioxide; nervous system, autonomic; Cardiovascular disease; respiration; Spectral analysis; RR interval; Heart rate; Clinical management; Analysis method; Autonomic nervous system; Baroreflex; Arterial pressure; Blood pressure; Baroreceptor; Comparative study
• DOI: 10.1161/01.HYP.0000179581.68566.7d
• ISSN: 0194-911X; 1524-4563

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 CO2 (CO2-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<0.05; and from 82.7±3 to 77.8±3.7 mm Hg, P<0.01, respectively). Controlled breathing (15/min) decreased systolic (to 142.8±3.9 mm Hg; P<0.05) but not diastolic blood pressure and decreased RR interval (P<0.05) without altering the baroreflex. Similar findings were seen in controls for RR interval. Slow breathing increased baroreflex sensitivity in hypertensives (from 5.8±0.7 to 10.3±2.0 ms/mm Hg; P<0.01) and controls (from 10.9±1.0 to 16.0±1.5 ms/mm Hg; P<0.001) without inducing hyperventilation. During spontaneous breathing, hypertensive subjects showed lower CO2 and faster breathing rate, suggesting hyperventilation and reduced baroreflex sensitivity (P<0.001 versus controls). Slow breathing reduces blood pressure and enhances baroreflex sensitivity in hypertensive patients. These effects appear potentially beneficial in the management of hypertension.