Is it worth it? Obstacle course racing

Stuart Heritage: ‘The best bit is the feeling of elation when you cross the finish line. Worst bit? Paying through the nose to be mildly electrocuted’

Is it worth it? Spinning classes

Stuart Heritage: ‘The worst bit invariably involves ramping up the resistance until you can barely move your legs, and being expected to whizz them around in double-time to a cack-handed techno song that never ends’