What is it? A group indoor cycling class that focuses on strength, speed and endurance.

How much does it cost? It’s usually free with your gym membership.

What does it promise? Between 45 minutes and an hour of all-out cardio. During a class, depending on how hard you push yourself, you can expect to burn more than 700 calories.

What’s it actually like? This varies wildly on the instructor. I’ve done ridiculously low-effort classes in swanky city-centre gyms full of swishy-haired yummy mummies. I’ve been screamed at by sergeant-majorish instructors whom I somehow seemed to have offended. I’ve ended some classes red-faced and exhausted and slumped over the handlebars. I prefer the last sort. You might not. A good, if disgusting, way to measure your effort is to see how much sweat you can wring out of your top afterwards.

Best and worst bit After the first few classes – when you get knackered after 30 seconds, can’t keep up and start hating the instructor, the rest of your group, and time itself for moving so slowly – you’ll begin to fall in line with the others in the class. That’s the best bit. 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. This will happen a lot.

Is it worth it? Spinning is a perfect, low-impact way to burn a lot of calories quickly. Almost every gym has a spin class in its timetable. Try a few before you commit, because not every instructor will be to your taste.