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WH Fitness Editor Bridie Wilkins put this viral challenge to the test

If I’m honest, I’ve always been pretty sceptical of workouts, like the 12-3-30 workout, that go viral on TikTok. As with anything that generates dizzying traction on social media, they can be created by anyone with an account, after all, so their merits aren’t usually backed by science – even the ones that go wild. The 12-3-30 workout (which has had 64million views so far) seemed different, though.

That's because rather than absolutely destroying you into a pool of sweat and tears, like most of the trends that have gone viral (the 600 calories in 60 minutes challenge, for example), it’s based purely on walking on a treadmill. It does sound easier than it is, but the fact that it’s accessible to pretty much everyone, and not governed by any dangerous parameters like calories burnt or time taken, made it a lot more credible, in my eyes.

After seeking confirmation from fourfive ambassador and celeb PT Jenny Francis-Townson that it’s (generally) safe, then, I decided to set myself my very own 12-3-30 workout challenge: one session every day for a week. Here’s what happened, and what Francis-Townson has to say about it.

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It was created by social media star Lauren Giraldo and follows a simple format:

You should also start with a five-minute warm-up and a five-minute cool-down, both without any incline.

Francis-Townson tells us that the trend certainly has its place. These are the most significant benefits of the trend:

Safety is the reason most TikTok workouts don’t quite sit with me, but I figured that walking couldn’t be half as dangerous as some other exercises out there, and Francis-Townson is on the same page.

‘Any exercise we do comes with an element of risk but walking - even at a fast pace - is an activity that is safe for most people to do without much trouble or concern,’ she tells me. ‘The fact that you are doing this steep uphill walk on a treadmill is also a lot safer than doing so outside, on uneven ground, when you run the risk of tripping.’

She did have some words of warning, though. ‘Walking on a very steep gradient for 30 minutes will put a lot of pressure on your lower back. If you don’t have solid posture or your core muscles aren’t strong enough to support you throughout, you could find your lower back takes the brunt of the strain which can lead to problems and pain.

‘If you’re not used to repetitive walking or running, you could also find you feel pain in knees or ankles or calves due to overuse and the repetitive nature of this form of exercise.’

To make sure that doesn’t come into fruition, she suggests doing the workout once or twice a week. (Although I did the workout every day for a week, know that this was all in the name of research. It’s neither wise nor sustainable to do the same.)

Plus, if you know you suffer with joint issues, ease yourself in with your own incline – there are still rewards to reap from walking for 30 minutes, no matter what the speed or incline.

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Should be approached with caution by:

This one isn’t really news, but turns out, walking on a treadmill for 30 minutes isn’t the one for me. The first two days were fine, but by day three I was well and truly dreading the idea of another 12-3-30 workout. Like Francis-Townson tells me, though, it’s ideal for anyone who wants to properly zone out while getting a sweat on. No reps to count, no equipment to keep guard of between sets, nada.

Luckily, Francis-Townson says it’s actually more efficient to nail one or two 12-3-30 workouts per week, alongside other forms of exercise. ‘The moment it becomes boring is the moment you’ll start finding excuses not to do it,’ she explains.

‘There’s no need to do it every day. I’d advise once or twice a week, alongside other strength training and bodyweight exercises.’ Good news for anyone in the same boat as me.

It obviously makes more sense for anyone with existing joint issues to punt for time on the treadmill over burpees and the like – it can actually be beneficial to walk over rest, to build up joint and bone strength – but know that the age-old adage ‘too much of a good thing’ applies.

I’ve never really experienced joint problems before, but about mid-way through my fourth 12-3-30 workout, my ankles began to feel uncomfortable and achey. Francis-Townson says this could be down to the trainers I was wearing, or simply too much of the same movement.

‘It could be that your shoes aren’t good for this sort of repetitive exercise,’ she says. ‘It could also be because you’re simply using muscles in your ankles that you don’t usually use this often. We have so many muscles and tendons leading from our legs to our feet, and walking uphill for long periods is going to put this under a lot of pressure.’

I’ve done plenty of long runs (albeit not on consecutive days) in the Adidas Ultraboost trainers I wore during this challenge, so I’d attribute the aches largely to doing the same movement, over and over. Rest is key – more on this to come.

If there’s one thing to take from this article, it’s that the 12-3-30 workout isn’t as easy as it seems. Naturally, it’s harder to do it for seven consecutive days like I did, but even the first session surprised me. I was sweating. Like, on par with HIIT-level sweating. I was also so hungry after every workout that I ate enough to feed a small village.

Francis-Townson reassures me this is to be expected: ‘You’ll definitely notice you’re hungrier because you’re using up so much energy by moving for so long with no rest. You’re also using your leg muscles to an extreme and causing micro tears in a similar way that you do in strength training, which means your body needs to repair, which requires energy in its own right.’

The first session became a fasted cardio session since I completed it before work at 7.30am (round of applause for me), and I find it hard to eat so early in the morning, but from day two onwards I made sure to have a banana with my coffee for some extra fuel. That certainly helped, but I practically doubled my typical portion sizes of breakfast, lunch and dinner.

What did I eat? I’ve been through the mill with eating issues, and I now strongly believe that food should be used for more than just fuel. It’s there to be enjoyed, so to that end, I ate whatever made me feel good at the time. Sweet potato is a staple, as is chicken, salmon and nuts – all of which I love, but also that packed in the protein to help my muscles recover.

Ever the optimist, I decided that on day three, I’d attempt a weight session after my 12-3-30 workout. Safe to say, it wasn’t my best. I could barely do five reps with weights that I can usually whack out 10-15 with.

Francis-Townson explains why: ‘If you want to strength train alongside this type of workout, I’d advise doing your resistance session first, then using the 12-3-30 workout as a finisher, or making sure you eat before your workout to give yourself that extra bit of energy.’

I basically had nothing left in the tank after giving the 12-3-30 workout my all.

Francis-Townson adds that a lack of hydration could have also played a part. ‘You lose a lot of water during a cardio workout like the 12-3-30 workout, so make sure you drink more water than usual.’

Experts claim that the 12-3-30 workout can help improve your stamina, but, TBH, I felt the opposite – the workouts got harder as the week went on. Francis-Townson says this is simply because I wasn’t taking any rest days.

‘It’s an intense workout,’ she begins. ‘And in order to build stamina, you need to give your body time to rest and recover, to come back stronger and with stamina. If you want to use the 12-3-30 workout as a way to build stamina, it’s vital you take rest days in between each session.’

The upshot? Almost all of the issues I ran into come back to not resting. So, if you’re keen to try the 12-3-30 workout, it’s imperative you take days off. Like I said, I took on the challenge in order to get some serious insight, not with the intention of continuing in the same vein.