12-3-30 workout for weight loss: how to do it

The 12-3-30 workout is a treadmill exercise that may help you shed pounds

Woman on treadmill doing the 12-3-30 workout
(Image credit: Getty)

If you follow fitness trends, you may have seen the 12-3-30 workout popping up all over social media. The treadmill workout was created by influencer Lauren Giraldo when she was looking for a simple and approachable way to get fit.

In a November 2020 TikTok video viewed over 12 million times, Giraldo explained why she created the workout. "I used to be so intimidated by the gym and it wasn't motivating. But now I go, I do this, and I can feel good about myself." Giraldo says the 12-3-30 workout has helped her lose 30 pounds without making any changes to her diet.

Many of us have a love/hate relationship with the treadmill. But jumping on one of the best treadmills can be great for fat loss, fitness levels, and even our mental health. And while there are lots of fat-burning treadmill workouts out there, the beauty of the 12-3-30 workout is its simplicity.

The workout is all about cranking up the gradient on a treadmill, replicating walking on a hill. Adding hills or inclines to a walking workout has been shown to increase your heart rate, calorie-burning, and target muscles in the hamstrings, glutes, and calves. 

How to do the 12-3-30 workout

First, jump on the treadmill and walk at 3mph, with the incline set to zero for 3-5 minutes - this will warm up your legs. 

Then set the timer to 30 minutes and increase the incline to 12% - you'll no doubt start to feel the difference pretty quickly

It's fine to hold on to the sides at first, especially if you feel unsteady - following the basic guidelines on how to use a treadmill safely is paramount. But to reap all the benefits from this workout you should try and move without holding on.

Unlike some other HIIT treadmill workouts you'll stick at an incline of 12% and speed of 3mph for the whole 30 mins - hence the workout's '12-3-30' name.

However, if you want to turn either of them up at intervals it's entirely your choice. You may find that after a month or so your body becomes more accustomed to the intensity of the workout, and you'll be able to turn the speed or incline up even higher.

To see the 12-3-30 workout in action, check out its creator getting her sweat on in the video below (skip to the 4:08 mark).

Lauren Giraldo's 12-3-30 workout

Is the 12-3-30 workout effective?

Since the 12-3-30 workout rose to prominence, scores of social media users have been copying Lauren's routine and showing off amazing results, from significant weight loss to taut, toned tummies. But how effective is it really?

well, the benefits of incline walking are numerous. Guido Basola, fitness trainer and founder of ELYSIUM gyms say it's a great routine if you're a beginner. "The first thing to be noted is that this is a fantastic route to go when looking to build consistency into your gym routine. It is simple and not as overwhelming as other programs, and will definitely increase your heart rate and help build and add to your base level of fitness."

The cardio element of the workout will also mean your heart rate will be challenged. "The addition of the hill will certainly get the blood pumping and start to increase your heart rate," says Basola. "This is great for calorie burn and posture - but keep those shoulder pinned back and chest high as you drive up that hill."

The 12-3-30 also offers one of the best leg workouts you can do on a treadmill, with Basola promising that you'll "definitely see changes in the quads, glutes, and hamstrings."

So, now for the golden question: just how many calories can you expect to burn with the 12-3-30 workout? If your main aim is fat loss, the 30-minute workout could see you burning up to 150 kcals - although, as with any exercise approach, you have to mix it up and keep your diet consistent too. "This workout will help you blitz away those unwanted pounds, although it's important to pair it with a healthy diet and a mix of weight training,' Basola advises, adding: "The more consistent you are the better the results."

Downsides to the 12-3-30 workout

Even though it's a great cardio workout, many who already regularly work out may not find it all that challenging. If that's the case for you, it could be saved for days when you're feeling tired or even for rest days when you want to move, but not exhaust your body.

If this workout challenges you to begin with, you may begin to hit a plateau after a couple of months as your fitness improves. "It’s a great workout, but don’t fall into the trap of complacency," says Basola. "It's important to note when you are getting fit and strong enough to keep challenging yourself, perhaps by increasing that speed gradually."

It's also important to note that walking or running on an incline - whether it's on a treadmill or outdoors - can affect both your posture and knees. Runner's knee is common in people who are constantly walking or running up hills, so try and switch it up with a flat walk every so often. With posture, keep your back straight, shoulders back, and look where you are going, in order to avoid any injuries.

Sarah Finley

Sarah is a freelance journalist who writes about fitness and wellbeing for the BBC, Woman&Home and Tech Radar. During lockdown she found her love of running outside again and now attempts to run around 50 miles a month. When it comes to other fitness, she loves a sweaty cardio session – although since she’s been working out from home she’s sure her downstairs neighbors aren’t too happy about it. She also loves to challenge herself - and has signed up to do hiking holidays, intense bootcamps and last year she went on her dream activity holiday: paddle boarding around deserted islands in Croatia. On her rest days, she loves to recover with a simple yoga flow session – the perfect antidote to her active fitness schedule.