I have been studying and practicing tibetan buddhism for a little over a year now, particularly dream yoga, but branched into some of the other practices. I'm always a skeptic but it is fascinating some of the stuff they can do. There is scientific evidence they can raise and lower their body temperatures through meditation, withstanding great heat/cold and deprivation conditions. I've played around with deprivation and what it has done for my mental health and body has surprised me. I'm but a novice, but I absolutely believe they are tapping into something scientific about the body/mind that is still unknown.

There are reasons to be extremely skeptical about some of their claims, but, some of it is very interesting and credible.