What is it?
Yoga, practiced in a room heated to 37-40°C. Usually it will be Bikram Yoga – that 90-minute, unvarying set of 26 postures – but there are studios popping up where you can also sweat through a little Hatha and Iyengar. You'll need to drink two litres of water before class and it will all end up on your towel. Bring a spare for showering, or rent one along with a mat, and wear as little clothing as possible.
It sounds awful, why should I do it?
Hot thighs! Better discipline! All of your skin sloughed off in a tidal wave of sweat! Some yogis claim Bikram doesn't have enough inversions and that the hot room makes you push dangerously beyond your natural flexibility. But the whole idea of yoga – any kind – is to have your own journey, and to work sympathetically with your body's abilities. So tell them to suck it. We like it hot because warmer muscles really are bendier muscles (so you can get your rear closer to your face), and because the sweat session leaves you as smooth and soft as a mango pancake. Also because we'd rate this on par with bear wrestling in terms of exercise extremity, yet we always feel some inner-peace despite the outer turmoil.