London's most hardcore gym workouts

ONE LDN has designed the hardest cardio-conditioning classes in London. Blending the very best Thailand-style fight club conditioning and HIIT, these sessions will leave you sweat-soaked and sore. Whether you're a seasoned pro or total beginner, you'll be feeling the pain and gains. Shadow boxing, agility stations, bag boxing, pad rounds, body weight HIIT and strength stations are the base of this class – as you can see, there's a lot to be getting on with. Bring water, you'll need it.

£20 per class, oneldn.com

Gymbox’s centrally-located gyms are all about the classes - there are heaps to choose from here, from the wittily named Saved by the Bell kettlebell class to daredevil options like aerial hoop. In the Holborn branch, a full size boxing ring dominates the space, while a well-stocked free weights area, two spin rooms, a climbing area and sprint track complete the set up. Our current favourite class is Express Ripped and Stripped, a weights-based work-out designed to chisel and define your body. Only 30 minutes, it's perfect for workers on a busy schedule. When the class is done, head back out onto the floor to the sounds of the DJ blasting out tunes from his booth – you’ll be pumped for the office in no time.

Membership starts from £69 per month. For more info, visit gymbox.com

Fancy some post-workout refreshment? Ours is a beer, thanks. They give away bottles of the stuff for free after some evening sessions at hip City gym 1Rebel. If that isn’t reason enough to get down there pronto, its new high intensity boxing concept, Rumble, might tempt you. You’re led into a large, dark basement room where you’re told glove up and are assigned your own 70kg punch bag. For the next 45 minutes, you’ll be instructed to GET ANGRY WITH YOUR BAG by throwing a flurry of punches and kicks, which are broken up by burpees, sit ups, pushups and squats. Be warned: there’s no rest time allowed, so you're guaranteed to come out a sweaty, quivering mess. Luckily, the industrial chic changing rooms come with high end lotions and potions to hide the damage. If beer after exercise sounds wrong, opt to refuel the sensible way courtesy of juice bar, Supernatural.

£16 - £20  per class. Wraps are £4 (to keep) and glove rental is £1 per use. For more info, visit 1rebel.co.uk

Step into the red-lit, sweaty basement at notorious bootcamp Barry’s and it feels as though you’ve just stepped into Dante’s inferno. You’ll spend the next hour on an exhausting turbo workout which’ll see you alternating between jogging and sprinting with inclines on the treadmill, and doing strength training weights exercises. The music is loud, the trainer’s shouting is even louder, and the crowd is toned and beautiful – celebrities including Victoria Beckham and Ellie Goulding are regulars. This isn’t one for sissies - even hardcore gymmers will be stretched to their limits here - but the hour flies, and you’re burning 1,000 calories a session. Which means that not being able to walk for the next two days will be totally worth it, right? Fitness instructor Sandy Macaskill explains why people keep coming back for more: "With most places you have to choose between cardio or strength training. But you need a combination of both if you want the sexiest body. Barry designed the weights and running programme in West Hollywood back in 1998 and it's been literally changing lives ever since. It really is the best in the world."

£20 for one class. For more info, visit barrysbootcamp.com

Lots of cheering, loud music and high fives happen at Boom Cycle’s classes. Don’t let that put you off though – inspired by US spinning cult SoulCycle, which counts the likes of Lady Gaga and David Beckham as fans – the sessions are addictively adrenaline-fuelled affairs. The class revolves around a carefully created soundtrack blasting out everything from hip hop to house, with the aim to keep you cycling to the beat. Some of London’s biggest DJs and record labels have even been asked to host special edition classes. Sack off the nightclub, this is the same thing – and you’re probably more likely to pull when you’re sober anyway.  

From £18. For more info, visit boomcycle.co.uk

If you want a hardcore fat burning workout that doesn’t involve jumping around like a maniac and pounding your joints, get yourself along to Speedflex. The point of the workout is low impact, high intensity training without next-day soreness (we clearly did something wrong when we went.) The circuit-based training concept combines cardiovascular and resistance training: you’ll spend 45 minutes using seven hydraulic Speedflex machines which calculate resistance based on your own body strength, combined with floor exercises. At the start of each session, you’re attached to a heart-rate monitor, the results of which are splashed across large screens so you - and everyone else - can track your progress. The potential shame of being in last place is a surefire way to get you repping harder.

£30 for a single session. For more info, visit speedflex.com

Centric: 3Tribes is the only place in London that offers a 50:50 mix of spinning/HIIT and yoga, so within the hour you get the high, the workout and of course the sweat, then hop off the bike to your yoga mat for vinyasa and deep long stretches. The studio has three rooms, each representing a different ‘tribe’: Rider, Warrior and Zen. Warrior does HIIT, Rider provides the spinning, and Zen unsurprisingly is yoga. You’ll go hard as hell in the first two rooms, but the cool-down period will be worth it.3tribes.co.uk 

There’ll be no hiding sheepishly at the back at Embody Fitness: you are the back. And the front. The one-on-one targeted PT classes at the boutique City gym are run by Olympic athletes, so be prepared to be put through your paces. Before you hit the gym floor, you’ll receive a nutrition consultation that comprises a hormonal breakdown, fat caliper test and a biomechanical assessment with a sports therapist. This basically means you’ll be batch cooking chicken meals for months, but it’s all part of the programme, and the before-and-after pictures on show in the gym reception are genuinely impressive. Expect lots of heavy lifting: the workouts include as many compound exercises as possible, teamed with old-school strongman exercises like the dreaded sled drag (where you drag a weighted sled across the room, a killer for the backs of thighs), finishing off with isolation moves including curls. "The aim is to create the greatest metabolic disturbance possible as well as increasing lean tissue gains," Chris Walton, director of personal training at Embody Fitness tells me. "The result is a spike in metabolism over the next 24-36 hours as well as an increase in resting metabolism as lean tissue is generated.” Yes it'll hurt, but you’re never not going to get pecs like Ryan Gosling the easy way. 

For more info, visit embodyfitness.co.uk

With its cool concrete walkways and spacious chill-out areas, Kensington's Core Collective says ‘swish cocktail lounge’ more than it says ‘sweaty gym.’ That’s not to say the boutique studio doesn’t take fitness seriously, though. As the name suggests, it specialises in workouts that’ll transform your beer belly into something far more taut and toned. Its flagship class, Velocity, is 45 minutes of hyper high intensity, athletic interval training, taking place in what looks a bit like Christian Grey’s sex dungeon. Pain is the name of the game here too – you work around the circuit doing moves in short bursts, including weighted box jumps, boxing, rowing, sit ups, pad kicks and tyre flips. You’re rewarded with a 20 second break between each exercise, and fluffy towels and Bamford products in the changing rooms after your workout. 

£28 per class (Core Collective is pay-as-you-go). For more info, visit core-collective.co.uk

If you plan on meeting up with friends/talking/moving after this class at retro dance studio Frame, don’t. After 90 minutes of high energy heart-racing cardio, work with sliders and mat exercises, the only thing you’ll going to be good for is bed. The class is divided into three sections to make sure you work out all your muscle groups, and the time is structured so that your heart will fluctuate between a million miles an hour, and something slightly more sustainable. Your whole body is getting a toning workout in this one, plus a whole section using gliders tackles your abs specifically. You might feel like you’re going to be sick at the time, and hobble around as though you’ve been beaten up the next day, but the vibe of this class is so much fun that you’ll be back again next week. Especially if you’re a stickler for punishment…

From £13. For more info visit moveyourframe.com

Working out on your own is old news for Equinox: its new buzzword for burning fat is ‘team competition’. The hour-long new Ropes & Rowers session pushes you and your ‘team’ to work together to complete the full body circuit in the fastest time possible. You'll be showing off to each other at the same time, obviously: there’s a leaderboard to encourage healthy competition. You're forced to power through the four station circuit where stations are made up of intervals using big medicine balls, a body weight section and work on the ropes and WaterRowers. Two rounds at each station with a short break in between has our heart pumping, our face sweating and our muscles really feeling the burn. If it means we're one step closer to looking like the ripped Adonis figures featured in the gym’s adverts, we're all for it. 

£186 with a £400 joining fee. For more info visit equinox.com

If you've been beavering away in the gym for months but your body's still not getting ripped, it could be down to your genes. Yep, sounds like a cop out, but scientists say that DNA is key to sporting ability - and apparently you're 33% more likely to lose weight using recommendations based on your genetic makeup. DNA Fit uses testing to work out what exercises an individual is suited to, as well as including tailored information about diet and recovery. You send a swab of your saliva off to the lab, along with a completed questionnaire, and two weeks later you'll receive a detailed personal diet and nutrition plan, plus tips about what your optimum workout will be. It'll even tell you if you're more suited to a sprint than a marathon, which might provide you with the handy excuse you were looking for…

£249 for the DNA kit, results and diet plan. For more info, visit dnafit.com