What is it? Someone who’ll force you into the best shape of your life, in return for approximately every single penny you’ll ever earn.

How much does it cost? It varies. Gus, my old trainer in south-east London, charged £50 an hour. But there seems to be no upper limit. Choose wisely.

What does it promise? A good trainer will consult with you about your lifestyle and goals, run diagnostics on your body, give you a tailored training programme, teach you proper technique and then hold your feet to the fire until you’re in the shape you want to be. The Journal of Sports Science & Medicine estimated that you’re 30% more likely to hit your goals with a personal trainer, which seems about right in my experience.

What’s it actually like? Great. The consultation itself, if done properly, is a thing to behold. I just had one at SIX3NINE in Covent Garden, and it was the most comprehensive diagnostic I’ve ever received. We discussed my history (good), my injuries (good), my stress levels (um), my sleeping patterns (oh) and my diet (yeesh), before a machine bluntly told me how out of shape I was. After putting me through my paces on the gym floor, the trainer created an utterly bespoke training and nutrition plan for me. It’s a level of service you just don’t get from plodding on a treadmill once a week.

Best and worst bit The consultation at SIX3NINE was absurdly thorough, but its packages can cost anything up to £2,500 for a six-week course. Like I said, choose wisely.

Is it worth it? If you can afford it, absolutely. If not, just go training with an enthusiastic friend.