Randomized Controlled Trial of Yoga and Biofeedback in Management of Hypertension

Treating hypertension with a device that slows and regularises breathing: a randomised, double-blind controlled study

“…Estimation of sample size was made at first for site I, using the data of Patel and North, 6 whose study had some similarity to our design, since treatments included breathing exercises compared to general relaxation. Standardised detectable difference (⌬/) for the systolic BP was found to be 0.78 (with pooled standard deviation), which provides a minimal group size of n ϭ 13 for comparing the treatments with a significance level of P Ͻ 0.05 with 80% power of test.…”

“…biofeedback and these methods have had some success in treating high blood pressure (BP). [2][3][4][5][6][7][8][9][10] Past research suggests that a slow and regular breathing pattern has a number of beneficial effects in the reflex control of the cardiovascular system. 11,12 However, the specific role played by breathing exercises in the sustained reduction of high BP has not been evaluated by well-controlled studies.…”

A comparison of the effects of biofeedback and meditation treatment on essential hypertension

“…To date, only one study by Datey (1977) reported by Patel (1973; and Patel and North (1975), respectively.…”

“…Blanchard and Miller (1977) categorize the two most recent studies by Patel (1975) and Patel and North (1975) as "controlled outcome studies 11 (p. 1403), which represent the "strongest design" (p. 1403) applicable to the study of hypertension. Blanchard and Miller (1977) state:…”

“…Patel and North (1975) also provided follow-up data at four and seven months, which indicated maintenance of blood pressure reductions obtained during treatment. Patel and North (1975) utilized a half-crossover design, in which the untreated control subjects were treated four months later, and showed significant decreases in blood pressure of the same magnitude as the treated subjects, thus providing "a very powerful demonstration of effects" (Blanchard and Miller, 1977, p. 1405).…”