yoga

Yes, provided it is learnt systematically from a guru of good reputation and then practicsed with strict discipline. My sister and brother in laws are yoga teachers and they have been practicing yoga for the last 15 years and have large number of followers. There are people who think that like any other crash course, it can be learnt in 15 or 20 days. One can learn a few asanas but the comprehensive can be learnt from a guru in about 6 months to 1 year, on 2 hours per day. Like too much is too bad, out of enthusiasm, one should not overdo, it may harm the body.