The Scientific Basis Of Yoga

To the Editor.— In order to assess the validity of claims of merit, at Banaras Hindu University we have initiated an extensive study on Yogic practices. Some of our observations are being published in Indian medical journals. A carefully conducted physiological, endocrine, metabolic, and neuropsychological study in a group of 12 young, normal, male volunteers (aged 23.0±3.36 years; weighing 123.0± 12.96 lb) undergoing a six-month systematic training course of "Hath Yoga" has shown beneficial effects; reduction in body weight and a significantly improved pattern of respiratory functions, with lowered rate of respiration, increased rate of expansion of the chest, and increased vital capacity and breath-holding time. They also showed evidence of development of resistance against physical stress in terms of stability of respiratory functions. An endocrine and metabolic assessment of these subjects showed enhanced adrenocortical activity, as evidenced by increased 17-hydroxycorticosteroid excretion, reduction in serum cholesterol level, reduction in blood