The health benefits of Isha Yoga that have been studied include its effect on short-term Heart rate variability. A small-scale study of 14 Isha Yoga practitioners with a matched control group of 14 non-practitioners concluded that Isha Yoga practitioners were more tolerant of exercise, with reduced risk of hypertension and better cardiac response to everyday stresses. Premature cardiac events like ischemia or infarction were also postulated to be less likely among practitioners. A study on the effects of Isha Yoga on menstrual disorders including Dysmenorrhea, Premenstrual syndrome and irregularity of menstrual flow and cycle was conducted involving 128 practitioners who responded through a survey questionnaire. The researchers concluded that the symptoms showed a reduction in severity after the respondents began regular practice of Isha Yoga. They also noted that respondents declared a reduced need for medical or surgical interventions and reduced impairment at work. The researchers recommended that Isha Yoga could serve as an adjunct therapy for menstrual disorders. A study focusing on sleep pattern benefits derived from practice of Isha Yoga was conducted with 15 male Isha Yoga practitioners with a matched control group of 15 non-practitioners. The study concluded that REM sleep, sleep efficiency and total sleep time was higher in practitioners, who also had fewer awakenings. A study of 89 practitioners before and after a 3-month meditation retreat concluded that a comparatively better performance was seen after the retreat in the Stroop task and in attentional blink task, suggesting improved attention span. Sadhguru, in his interviews, talks about inner engineering as a process of knowing the immense capabilities your body has that you never thought of. Once you attain a balance of mind, mind becomes a useful instrument, following your orders, and you can achieve any height of success. You reach a state of unabated bliss and ecstasy, something we have been long deprived of.