Spinning is a bit like Marmite: you either love it or hate it. But no matter how you feel about spending time on that stationary bike, you can’t deny that it’s one of the most intense forms of exercise out there. 

One moment, you’re pulling yourself up onto the saddle, clipping in your feet and taking those first few spins, and the next, your thighs are screaming, your heart rate is through the roof, and you’ve got sweat dripping from every part of your body.

I consider myself a relatively fit person – I’m currently nearing the end of training for my first half marathon – but I’ve always been taken aback by how utterly spent I feel at the end of a class each time I’ve gone. That’s not a bad thing – it feels good to really give it your all every once in a while – but it is different to the feeling I’m left with after, say, a big run or hour-long gym session.

So what is it about spinning in particular that makes it such an intense workout? And what areas of the body does it work? We asked two spinning experts to share their perspective.  

While the legs do the majority of the work in a spin class, spinning is really a full-body workout because you need to use your arms and core to stay stable while riding the bike. Some spin classes also incorporate hand weights and presses on the handlebars to incorporate upper body work, too.

When you up the resistance on the bike (as most classes will ask you to do), these areas are worked even harder. “Increasing resistance on the bike will increase the weight through the legs, resulting in more of a leg workout,” explains Marie Napier, head of ride at Psycle. “Using higher resistance will require more work in your stomach muscles – providing your posture is correct.”

Specific areas of the legs will also be worked harder than others, explains Kate Beckett, an instructor at the studio Ride Republic. “As you move between seated and standing, your quads, glutes, hip flexors and hamstrings are all going to be working,” she says. “You’ll feel your glutes more when you stand and those quads will be burning more when you’re in the saddle.” 

Spinning gets particularly sweaty because of the variety of muscle groups it uses – as the muscles contract, they release heat energy, which is distributed around the body. This triggers the body’s cooling response: sweat.

“Spin classes are designed to elevate your heart rate and challenge your body and mind,” Napier adds. “When our heart rate goes up, our body temperature increases, and because spin classes tend to incorporate interval training and physical pushes, the heart rate rises even further – resulting in a hot and sweaty experience.”

The amount of time you’re allowed to recover between pushes can also vary – with some classes opting for shorter breaks to make things feel more intense, Beckett adds. 

“Depending on the style of the class, there’s potentially less recovery than work, which means the intensity is sustained over long periods of time,” she says. “This means your body has to work harder to keep supplying energy to the muscles and keep the pedals turning.”

The fact that spin is done indoors in an enclosed environment – unlike when you’re cycling on the road – also means you don’t get exposed to any airflow while working out, making it harder for your sweat to evaporate and cool you down. In the end, the only place it can go is a puddle on the floor. Lovely stuff.  

While most spin classes incorporate an intense workout, it’s the spin atmosphere which can make things feel even more intense. Spin classes – at least those in spin studios – are often conducted in the dark, with flashing lights and pumping music coming together to produce the final experience.

Different studios employ different techniques to give the workout a unique experience. “Each Psycle class is structured to guide the rider through a specific journey from the warm-up through to power pushes, strength and conditioning and our arm-focused weights track,” Napier explains. “The incredible music – which is individually curated by the instructor – also helps you to stay immersed in the experience.” 

From producing endorphins to improving muscular endurance, spin can offer a whole host of benefits. It’s why it’s so often held up as a great low-impact exercise option for older adults or those recovering from injuries – but it’s important not to be aware of the dangers of taking spin too far.

Indeed, experts are keen to stress that it’s easy for those who are new to spinning to overexert themselves – previous research has shown that an hour of spinning produces the same biochemical markers as a heart attack. 

While that doesn’t mean spinning gives you a heart attack – those markers gradually decrease following a class, compared to after a heart attack where they can stay elevated for several days – but it is a sign of just how hard your heart has to work to keep up during a spin class.  

Separate research has found that, even in trained athletes, the most intense spin sessions can push people past the threshold where exercise is beneficial – known as nonfunctional overreaching.

That doesn’t mean you should stay away from spin – it’s a brilliant form of exercise that can offer benefits for the whole body – but you should introduce it gradually if you’re trying it for the first time, and try not to do too many spin sessions back to back (although the DOMS will probably stop you from doing that). 

Images: Getty