Progressive increase in critical flicker fusion frequency following yoga training

The critical flicker fusion frequency (CFF) is the frequency at which a flickering stimulus is perceived to be steady, with higher values suggesting greater perceptual accuracy. The CFF was measured in two age-matched groups of healthy male volunteers whose ages ranged from 25 to 39 years, with 18 subjects in each group. After baseline assessments one group (yoga group) received yoga training, while the other group (control group) carried on with their routine activities. Yoga practices included asanas, pranayamas, kriyas, meditation, devotional sessions and lectures on the theory of yoga. After 10 days neither group showed a change in CFF. However, at 20 and at 30 days the yoga group showed significant increases in CFF by 11.1% and 14.9%, respectively (two factor ANOVA, Tukey multiple comparison test). The control group showed no change at the day 20 and day 30 followup.