In between spin classes it's a good idea to do seated squats, single leg squats and walking lunges at home.

Dumbbells are cheap and easy to store and will help with upper and lower body exercises such as bicep curls, stomach crunches, chest presses and leg squats.

In one, he asked groups of strangers to hold their hands in icy water for as long as possible, hold a series of leg squats, and eat hot chili peppers.