*Check out Charlotte's gallery above by scrolling with your arrow keys*

This month, FHM investigates why millions of us are forsaking the gym in favour of trendy fitness crazes like military fitness and hot yoga.

We caught up with sexy yoga expert and FHM Girlfriend Charlotte to get you the low-down. Here's what you need to know:


Hot yoga and Bikram yoga are the same thing. You do yoga in a room that's super-hot. As soon as you walk in the room, you start sweating and the whole thing is basically a battle to see if you can stay in the room for the full session.


It's more relaxing than going to a normal gym. You don't actually have to work that hard and you sweat a lot more and burn more calories.


Stand at the back if it's your first class. You can get a bit light-headed. Normally, you start off with a 45-minute class and then see if you can do 60. I've done 90 minutes before but I nearly died...


It feels like you've dropped a stone straight away. As soon as you drink, you'll put it back on, but you'll still be toning up your body and getting rid of loads of toxins. It's great if you've had a heavy weekend.


Wear very minimal clothes. I just wear shorts and a tiny top. I wore leggings the first couple of times but they're glued to you when it comes round to getting them off.


Want an idea of what you're letting yourself in for? Check out FHM man Dan having his spirit broken below...

Get the FHM low-down on whether these faddy fitness regimes are really worth your hard-earned dosh in this month's issue...