Hell-bent: Transcending pain in competitive yoga
3 January 2013 Last updated at 00:07 GMT
For the millions of people who have made a new year's resolution to lose weight in 2013, yoga is an enticing option.
But they are fooling themselves if they think it will be an easy route to a better body and a more relaxed mind.
In a bid to lose 45lbs (20.4kg), Benjamin Lorr began attending super-heated Bikram yoga classes in Brooklyn, New York.
It was the beginning of a sweaty two-year journey which he documented in his book "Hell-Bent: Obsession, Pain, and the Search for Something Like Transcendence in Competitive Yoga".
The BBC attended a class at Bikram Lower East Side, one of Mr Lorr's favourite studios, and filmed him practising in his apartment with US Yoga gold medallist Courtney Mace.
Produced by Anna Bressanin; camera by Ilya Shnitser