The 12-3-30 Workout Explained And How To Safely Incorporate It Into Your Routine

Proponents of the viral 12-3-30—a treadmill-based cardio workout—tout it as a simple way to burn calories, lose weight, and grow your glutes, all while boosting your fitness and cardiovascular health.

But how effective is it really, and is it a good workout for everyone?

The name may sound confusing, but the 12-3-30 workout is pretty straightforward. Each number represents a component of the workout: To do it, you increase the treadmill incline level to 12%, set the speed to 3 miles per hour (MPH), and walk for 30 minutes.

However, keep in mind these numbers are to be used as guidelines. If your treadmill incline doesn't go up to 12%, or the speed is too fast or slow, you can adjust accordingly to suit your fitness level.

The workout goal is to keep your heart rate elevated by walking at a moderate pace on an incline.

The 12-3-30 workout was created by social media influencer Lauren Giraldo in 2019 when she shared it as a YouTube video. However, it wasn't until Giraldo posted the workout on TikTok and Instagram in 2020 that it exploded in popularity.

While it's easy to dismiss the 12-3-30 workout as another fleeting fitness trend, don't knock it until you try it.

According to Giraldo, her treadmill routine has helped her shed 30 pounds (and keep it off for over two years) while gaining more confidence in the gym.

Over 1,000 YouTube commenters have echoed her claims. They've also said the workout is much harder than it appears, has given them the motivation to go to the gym, and has helped them overcome gym intimidation.

While these benefits are merely anecdotal, experts back some of them up. Kate Meier, CPT, a certified personal trainer with Gym Garage Reviews, tells mindbodygreen that "Walking is a great, low-impact form of cardio that comes with the benefits of any cardiovascular exercise: improving your overall fitness, burning fat, and improving heart health."

Incline walking especially works the lower body, including the glutes, quads, and hamstrings, she adds.

"The 12-3-30 workout is a low steady-state cardio that benefits your cardiovascular system," says Dan Johnston, CPT, a certified personal trainer and strength and conditioning coach.

While any type of cardio exercise will increase your daily energy expenditure, incline walking ramps up the intensity of your walk and elevates your heart rate into the fat-burning zone.

Though the number of calories you'll burn walking on an incline depends on several factors—such as your age, size, and fitness level—a 2012 study published in the Journal of Biomechanics1 found that energy expenditure increased on average by 17% on a 5% incline and by 32% on a 10% incline.

Translation: For a 150-pound person, every 1% increase in incline burns roughly 10 extra calories per mile over flat-surface walking.

Another benefit of incline walking is that it can activate several muscles in your lower body, including your glutes, hamstrings, and quads.

Also, it can increase stability in your leg muscles2, which boosts joint health and mobility in your hips, knees, and ankles.

Since the 12-3-30 workout is a type of steady-state cardiovascular exercise, it can boost your heart health by keeping your heart rate elevated3 for a sustained duration.

Having a healthy heart is critical for several aspects of overall well-being4.

Depending on your fitness goals, there may be a better workout for you than the 12-3-30. That's because it doesn't increase strength or improve flexibility, two key components for overall fitness.

Giraldo (the workout's creator) claims to do the 12-3-30 five days a week with no other exercise. While this is good for cardiovascular health, it misses out on the many benefits of strength training and overall mobility.

"Furthermore, the 12-3-30 could be too intense for people who haven't done this type of exercise before," says Johnston.

And while incline walking can strengthen your lower body, don't rely on it as an effective exercise to significantly target your glutes.

"The 12-3-30 can be a complementary form of cardio if your goal is to grow your glutes, but I would also include plenty of glute-centric resistance training exercise into your workouts," advises Meier.

Johnston adds that people wanting to reap the benefits of low-impact steady-state cardio while putting on muscle and increasing flexibility should combine the 12-3-30 with a well-rounded strength training and flexibility program.

If you're looking for other exercises to mix up your routine that deliver similar results as the 12-3-30, we got you covered.

Incorporate lower-body resistance training exercises, such as lunges, squats, Romanian dead lifts, hip thrusts, split squats, and step-ups. These are excellent movements to help strengthen your glutes.

The 12-3-30 treadmill workout is an effective way to increase aerobic fitness, burn calories, boost your mood, and improve your heart health while engaging muscles in your lower body.

Combined with a healthy diet and calorie deficit, it can also promote healthy weight loss.

However, there's no easy solution or magic pill for losing weight or getting fit.