Staring at the TV, pounding away on the treadmill with your headphones in can only be motivational for so long.
You’ll first notice you’re losing your workout mojo when you find any excuse not to go to the gym: I really must tidy my room; that paint really does deserve to be watched as it dries.
But rather than stop altogether and pile on the pounds as you console yourself with the myth that you’ve increased your metabolism with all those years of exercise, find something that’s fun and burns calories.
London is full of weird and wonderful workouts, where you’ll be so caught up with the madness of it all, you’ll forget it’s actually good for you.
Here, we showcase our top three.
Great Gorilla Run
What: This is not your average fun run. Don a gorilla suit and join hundreds of others who make the 7km trek from the City, taking in sights such as Tower Bridge, the Thames and the Tate Modern. And it’s all for a good cause.
You’ll be sweating your bits and pieces off to raise cash to help save wild mountain gorillas – and you’ll get to see Adam Garcia in the process, as the Aussie actor will also be running.
The Great Gorilla run kicked off in 2003, and has so far raised more than £1m for biodiversity conservation and poverty reduction projects in central Africa.
Cost: You’ll need to pay £80 to register, which covers the cost of your gorilla costume, which you get to keep, and commit to raising £400 – easy money if you badger your mates on a night down the pub.
When: September 22, at 10.30am (registration from 8.30am)
Wacky rating: 5/5
What: Continuing the monkey theme, Go Ape offers an outdoor workout with a difference – you’ll be swinging through the forest on zip wires, crossing wooden walkways and bridges and climbing tree-top ladders.
The adventure company has conducted a health and fitness study, revealing that, based on an average of 100-120 minutes in the park, women will burn about 510 calories, while for men it’s 660 (equivalent to a six-inch pepperoni pizza) during the above-ground fun.
Cost: £30 for gorillas (adults).
When: Throughout the day. Trent Park, near Enfield, is a short walk from Cockfosters Tube
Wacky rating: 4/5
What: Get out your spandex and your legwarmers for a trip back to the Eighties in this fast-paced, 60-minute spin class with a difference.
With classic sing-along tunes blaring in the background – think Abba and Bonnie Tyler – you’ll pedal away, working hard to keep cycling to the beat.
“We’ve seen all sorts of outfits, from leopard print leggings to neon head bands and glitter leotards,” instructor Gerard Luis says. The class offers a great cardio workout, during which you could burn off up to 1000 calories.
You’ll shape up your legs and bum as it uses large muscle groups in your legs – and the music will keep you motivated.
“People ask what the most effective cardio workout is and I always tell them it has to be something that you enjoy – there’s no way anyone will stick to something that don’t like,” Luis adds.
“We make a point of mixing things up a bit to add extra excitement to the classes so you’ll find live DJs and themed classes popping up regularly.”
When: Classes run every few weeks at its studio in Shoreditch.
Wacky rating: 4/5
Photos: Thinkstock; Getty