Effects of slow breathing exercise on cardiovascular functions, pulmonary functions & galvanic skin resistance in healthy human volunteers - a pilot study.

BACKGROUND & OBJECTIVES: Regular practice of slow breathing has been shown to improve cardiovascular and respiratory functions and to decrease the effects of stress. This pilot study was planned to evaluate the short term effects of pranayama on cardiovascular functions, pulmonary functions and galvanic skin resistance (GSR) which mirrors sympathetic tone, and to evaluate the changes that appear within a short span of one week following slow breathing techniques. METHODS: Eleven normal healthy volunteers were randomized into Pranayama group (n=6) and a non-Pranayama control group (n=5); the pranayama volunteers were trained in pranayama, the technique being Anuloma-Viloma pranayama with Kumbhak. All the 11 volunteers were made to sit in similar environment for two sessions of 20 min each for seven days, while the pranayama volunteers performed slow breathing under supervision, the control group relaxed without conscious control on breathing. Pulse, GSR, blood pressure (BP) and pulmonary function tests (PFT) were measured before and after the 7-day programme in all the volunteers. RESULTS: While no significant changes were observed in BP and PFT, an overall reduction in pulse rate was observed in all the eleven volunteers; this reduction might have resulted from the relaxation and the environment. Statistically significant changes were observed in the Pranayama group volunteers in the GSR values during standing phases indicating that regular practice of Pranayama causes a reduction in the sympathetic tone within a period as short as 7 days. INTERPRETATION & CONCLUSIONS: Beneficial effects of pranayama started appearing within a week of regular practice, and the first change appeared to be a reduction in sympathetic tone.

Estrogen protection against coronary heart disease: are the relevant effects of estrogen mediated through its effects on uterus--such as the induction of menstruation, increased bleeding, and the facilitation of pregnancy?

Women in the age group of 20-50 are shown to have much less susceptibility to Coronary Heart Disease (CHD) and other atherosclerotic diseases as compared to men. Exact cause of which is not precisely known and estrogen is constantly shown to be associated with this phenomenon. Improvement of serum HDL concentration and improvement of endothelial functions are some of the proposed mechanisms through which estrogen is believed to mediate this effect. Estrogen therapy however has failed to protect women with bilateral oophorectomy and hysterectomy. Similarly inability of endogenous estrogen to protect women, who have undergone hysterectomy with functioning ovaries from CHD, questions the currently accepted mechanisms through which estrogen brings about these protective effects. Ineffectiveness of estrogen therapy as prophylaxis against CHD in men further questions the credibility of the currently accepted protective mechanisms of estrogen. Estrogen has variety of effects of on uterus, to induce menstruation, to induce bleeding, facilitative role in pregnancy, fetal growth and development. As these physiological effects either directly or indirectly result in loss of cholesterol from cardiovascular compartment, it is proposed that cholesterol-losing effects of estrogen are more important than its presently believed beneficial effects. The small amount that is lost causes movement of cholesterol from atheroma towards plasma and thereby retards the progress of atherosclerosis. These cholesterol-losing effects of estrogen enable women to enjoy freedom from CHD during their reproductive age, as compared to men of comparable age group. Statistical data obtained from blood donors indirectly support the proposed hypothesis.