What is the 12-3-30 workout? A personal trainer explains how to do the treadmill workout

What is the 12-3-30 workout and is it worth the hype? Here, a personal trainer explains what the treadmill workout is all about, its benefits, and more

Woman's hands pressing buttons to start treadmill at the gym, representing 12-3-30 workout
(Image credit: Getty Images)

The 12-3-30 workout continues to be one of the most popular treadmill workouts around - and for good reason. The simple setup is a great option for anyone new to exercise, looking to get fitter, maintain muscle, and improve their balance in 2024. 

The 12-3-30 workout prioritises incline walking as a workout over high-intensity running, offering a lower-impact, joint-friendly, and beginner-friendly alternative to running. These sessions have been popular ever since treadmills first made their way into gyms but fitness influencer Lauren Giraldo brought them back into the mainstream recently after her video went viral on TikTok. 

Talking about the treadmill workout, Giraldo said: "I used to be so intimidated by the gym, and it wasn’t motivating. But now I go and do this one thing, and I can feel good about myself." Looking to start walking 30 minutes a day? Here's what a personal trainer wants you to know about the 12-3-30 workout, its benefits, and how to do it right. 

What is the 12-3-30 workout?

The 12-3-30 workout is a very simple concept. Lace up your trainers and hop on a treadmill. Adjust your incline to 12, the speed to 3mph (which translates to 4.8kph for those using a treadmill made in the UK), and set a timer for 30 minutes on your machine or your pick of the best fitness trackers

That's it - you'll then walk for 30 minutes at this incline and speed. To get started, all you need is access to a treadmill, a spare half an hour in your day, and a good pair of running shoes

"The idea behind this workout is to achieve an efficient and effective cardiovascular workout compared to regular flat-surface walking, while also toning and engaging various muscle groups," says Amanda Place, a personal trainer and the founder of Sculptrition. "It's an effective way to burn calories and promote overall fitness."

How to do the 12-3-30 workout

  1. Clear a space and warm up with some dynamic stretches, focusing on the lower body.
  2. Jump on the treadmill and start walking, starting on the flat incline, for five minutes. 
  3. Turn the incline on the treadmill to 12 (12%)
  4. Turn the speed to 3 mph (4.8kmph)
  5. Walk for 30 minutes
  6. Cool down for five minutes by walking on the treadmill at 0 incline
  7. Stretch out again with some static stretches. Focus on the lower body again - especially the quadriceps, calves, glutes, and hip flexors. For a session to follow, try one of the best stretching apps

Unlike HIIT treadmill workouts, there are no intervals or changes of pace. While this sounds like it should be easier, moving at one speed at one (high) include level may not be as easy as you think. 

To get started, you could set the incline to 3 or 4 instead of 12 and challenge yourself to hold the pace for as long as possible. Then, when you feel ready to do so, build up your time and gradient as you get fitter and stronger. The speed at which you progress will be different for everyone, so don’t compare yourself - work at the level that’s right for you. It should feel challenging, but not so much so that you feel out of breath and can't continue. 

Adapt the gradients and paces for your level and consider breaking the 30 minutes up into intervals with short rests, and building up to 30 minutes over four to six weeks if you're a total beginner. 

It's also important to maintain good form as you walk. Engage your core, keep your shoulders back and your head up. Always look straight ahead, rather than down at your feet on the treadmill. 

Amanda Place
Amanda Place

Award-winning personal trainer Amanda Place is the founder of Sculptrition, a platform that helps you quit fad diets, find balance and create a healthy lifestyle. She specialises in health and fitness coaching for high-achieving women, helping them transform their body and mind, improve their health and become the best versions of themselves. 

Benefits of the 12-3-30 workout

It builds fitness and stamina

It is certainly a good workout for building fitness, with all the benefits of running for women, without the stress on the joints. The treadmill isn't all about running. Power walking on the flat or even hills can provide a great workout, often with less impact on joints. 

A 30-minute walk with a high gradient such as 12% working at a strong steady intensity will certainly get your heart rate up, be a test for your posture, and work your core muscles with one of the best core exercises to do at home. You will also have to engage and drive with your glute muscles to maintain your position on the treadmill belt.

While it's not the most versatile workout in the world, there are ways you can adjust the 12-3-30 workout to make it harder. For instance, adding ankle weights will add some resistance against your legs and glutes and require you to really focus on your core stability. 

It aids weight loss

For those looking to lose weight healthily, the 12-30-30 workout offers many benefits. Firstly, it's easier to stay consistent with this workout compared to a challenge like running 30 minutes a day

This is important because when it comes to weight loss, it's all about calories in versus calories out (at least to begin with). Reducing the number of calories you consume while burning more - through regular low-impact workouts like these - will put you in a calorie deficit for weight loss

The 12-3-30 workout could even help you lose weight if you just do it once a week. One of the top reasons many people stop working out is boredom, a study by the University of Konstanz highlights. If you're doing other forms of exercise doing the week and you're looking for something to spice things up a little by the weekend, this workout could be just the thing. 

It improves heart health

It's well-established by governing health bodies and expert facilities, including the Mayo Clinic and Ohio State University, that aerobic exercise like walking and running helps keep the heart healthy. The extra effort makes it work harder to push blood (containing oxygen) around the body and as the heart is a muscle just like any other, the more you use it, the more effective it is. In turn, this lowers blood pressure and reduces the risk of heart disease, type 2 diabetes, stroke, and other serious diseases. 

It's a low impact exercise

The softer surface of the treadmill and slower pace put less pressure on the joints in the 12-3-30 workout, especially when compared to activities like running. This means less chance of injury and discomfort post-workout and more chance of round two the following day. 

"Unlike high-impact exercises, such as running or jumping, the 12-3-30 workout is low-impact. This makes it suitable for individuals with joint issues or new to exercise," says Place.

Disadvantages of the 12-3-30 workout

Limited variation

The 12-3-30 workout is an effective one, says Place, but it does lack variation. Variation is important as different exercises are likely to recruit different muscle groups and mixing up your workouts can help prevent overuse injuries and stress to the worked muscles. 

"This workout primarily targets the lower body muscles, neglecting the upper body, and additional exercises are necessary to achieve balanced fitness," says Place. "Relying solely on this routine may also lead to monotony and hinder long-term commitment to fitness."

You may hit an exercise plateau

To get fitter and stronger, it's important to make your workouts progressively harder. Unfortunately, unless you change one of the metrics of the treadmill, this doesn't happen easily with 12-3-30 workout. 

"Over time, your body may adapt to the 12-3-30 routine, causing diminished results. It's crucial to periodically increase the incline or speed to continue progressing," says Place. 

It may not be suitable for everyone

As noted, the 12-3-30 workout is a good choice for newcomers to cardio exercise or those recovering from injuries. However, Place says, "the 12-3-30 workout may not provide the high-intensity challenge sought by more advanced fitness enthusiasts". 

Equally though, if you are new to exercise, it's quite easy to push yourself a little too hard, too early, as 12 is a relatively high incline on a treadmill. This can lead to lower back pain, for instance. Anyone who suffers from upper and lower back pain should be careful when walking at this incline continuously for 30 minutes. 

"Some individuals may push themselves too hard, resulting in overexertion or injury. It's essential to start at an appropriate fitness level and gradually increase intensity," says the PT. 

Who is the 12-3-30 workout good for?

The 12-3-30 workout is good for anyone new to fitness or anyone looking to increase the amount of cardiovascular exercise they do without turning to a high-intensity activity like running. For those returning to exercise after some time away, it's a great workout for building up your endurance again. 

Plus, for those who normally aren't fans of running or spinning because of the intense 'out of breath' feeling, walking on a treadmill at an incline could be a great fitness solution. The 12-3-30 workout is a form of LISS cardio, which means you're going for longer at a slower pace. Much like swimming, soft hiking or Nordic walking, it's a gentler way to get your heart rate up and improve your cardiovascular health.

Can you do the 12-3-30 workout every day? 

Yes, if you're looking for an exercise to do every day, the 12-3-30 workout could be a great choice. The NHS recommends 150 minutes of moderate exercise every week, divided up across seven days. You'd only need to do this workout five times a week to hit this target, leaving plenty of time for rest and recovery. 

However, the experts recommend alternating between the 12-3-30 and other types of exercise - such as strength training at home, Pilates, or yoga mat workouts to help maintain and strengthen the muscles neglected by the treadmill workout. For example, you could do the 12-3-30 three times a week and a type of strength training twice a week to hit the quota. 

Does 12-3-30 actually burn fat?

Yes, another benefit of the 12-3-30 workout is that it can help you lose fat. While it's not possible to spot-reduce fat, doing the 12-3-30 workout can help you burn calories and get into a good calorie deficit. As noted, this will help you lose weight overall, which will include losing fat around any particular areas you're concerned about.

While the incline on the 12-3-30 workout does add some resistance, incorporating some off-treadmill strength training into your workout will help you build muscle, which speeds up your metabolism in turn and means you'll burn more calories at rest.

Health Editor Grace Walsh doing the 12-3-30 workout at the gym

(Image credit: Grace Walsh / Future)

I tried the 12-3-30 workout for two weeks - is it worth the hype? 

The 12-30-30 workout is a good one to add into rotation in my opinion, as woman&home's digital health editor and as someone who regularly works out. It activates muscles in the lower body and although 3mph may be an average walking pace on flat ground, it gets the heart rate up and pushes the cardiovascular system at an incline, making it a suitable challenge for those looking to get fitter in coming months. 

However, if you can keep up the motivation to simply walk on a treadmill for 30 minutes, I salute you. I tried the 12-30-30 workout myself every day for two weeks and found the lack of variety to be the main issue with the session every time. Using the same muscles every day, walking in just one direction, in the same spot, grew mentally stale after a while. I found myself relying heavily on podcasts and playlists, especially toward the end of the two weeks and I was clock-watching right until the end. 

If you're doing the 12-3-30 workout from home, it's important to invest in the right treadmill. Walking pads are everywhere at the moment and offer a great way to get your steps in for the day - but they are not suitable for this workout. The incline won't be high enough. Instead, prepare clear space and invest in a gym-ready treadmill with an incline of at least 12%.  

Grace Walsh
Health Channel Editor

Grace Walsh is woman&home's Health Channel Editor, working across the areas of fitness, nutrition, sleep, mental health, relationships, and sex. In 2024, she will be taking on her second marathon in Rome, cycling from Manchester to London (350km) for charity, and qualifying as a certified personal trainer.

A digital journalist with over six years experience as a writer and editor for UK publications, Grace has covered (almost) everything in the world of health and wellbeing with bylines in Cosmopolitan, Red, The i Paper, GoodtoKnow, and more. 

With contributions from