A micro HIIT workout is the regime Londoners need

What can you achieve in 15 minutes?

A few emails, perhaps, or pawing slack-jawed through Instagram? Alternatively: how about — deep breath — granite abs, sculpted shoulders and obliques you could bounce a shiny penny off? The (inevitable) catch does not involve flogging your soul to the devil — though it does mean working like a bat out of hell for a 15-minute stretch that will feel like fiery eternity.

This is the Faustian pact of micro-HIIT, the latest iteration of the high intensity interval training model that is the through line of all of London’s hardest and most efficient workouts.

But instead of toiling through a 45-minute class, sweat cascading from every pore, you could do that, but only for 15 minutes, and see results.

Your normal HIIT class might involve three minutes on and a minute off. Micro-HIIT is more like 20 seconds on, 10 to recover — and start again. It sounds easy until you’re trying to force your jellied legs into another tuck jump. Saying that, you can endure (almost) anything for 20 seconds.

As Matt Delaney, national manager of innovation at Equinox, says: “Micro HIIT helps you perform the intervals the way they were intended, with short duration high impact activity followed by a longer recovery period.” Convinced? At Equinox’s shiny new club in Bishopsgate — five storeys of sleek studios and hardwood floors — its work-hard, work-out-harder City clientele are flocking to Core Conditioning, a 15-minute micro-HIIT class that works your core, back strength and flexibility, using a combination of moves including weighted lunges and planks (grimace).

The Clock is where London’s cash-rich nad time-poor work out: at its plush studios in Marylebone and Notting Hill, super trainer Zana Morris leads clients in 15-minute highly targeted workouts, to rhapsodic recommendations. Speaking of the cash-rich, on the fourth floor of Harvey Nichols you’ll find a queue of pert buttocks in lululemon leggings queuing for the Car.o.l bike — an AI-powered spin machine that promises to whip you into shape in a ludicrous 40 seconds, in a workout that it claims delivers the same cardio benefits as a 45-minute jog. A whizzy AI algorithm personalises your resistance to ensure you are working at maximum intensity. Join the queue (lululemon mandatory).