Materials and Methods
Two hundred and eighteen subjects took part in the study. One hundred and nine volunteers (51 males and 58 females) in the age group of 20 to 60 years, who practiced yoga regularly for over five years for a period of one hour daily, performed a bout of moderate exercise and a bout of strenuous exercise. Blood samples were collected between 7 and 8 AM; (a) just before performing exercise (baseline); (b) immediately at the end of one bout of moderate exercise and; (c) at the end of one bout of strenuous exercise, for analysis of IL-6 and TNF-α. Strenuous exercise was performed on a different day. All subjects performed exercise under supervision. Anthropometrically matched, age matched and gender matched subjects, who did not practice yoga (non-yoga group) were chosen as controls (non-yoga, n=109). The non-yoga group also performed similar exercise. Informed written consent was obtained from all the subjects volunteering to participate in the study. The study protocol was approved by the institutional ethics committee.
Sample size estimation was carried out based on a pilot study [10] in which it was found that there was a significant difference in TNF-α between yoga and non-yoga group before and after strenuous exercise. Considering an effect size of 0.4 and with the power of 80 and desired confidence level of 95 percent, the sample size was estimated to be 100 in each group.