What to Know About the Viral 12-3-30 Workout

Ever since TikToker Lauren Giraldo first posted about the 12-3-30 workout in late 2020, it’s been making the rounds as a quick way to slim down.

Giraldo says it’s a game-changer that helped her lose 30 pounds. She also claims she doesn’t watch what she eats at all — and her weight-loss success is all thanks to this workout.

The formula is simple: Hit the treadmill, turn it up to the highest incline setting (12%), and walk at 3 miles per hour for 30 minutes. Repeat about five times a week, or as often as you can.

But TikTok is famous for trends that sometimes fizzle out IRL or don’t have much scientific research to back them up. So, could the 12-3-30 workout actually help you lose weight? And if so, is it worth it?

We asked two running coaches to break down how it works and share whether they’d recommend it for a safe and effective weight-loss strategy. Here’s what they had to say:

First thing’s first: Are you going to injure yourself if you jump right into this? Walking uphill might not sound so difficult, but a 12% incline is very steep. To put this into perspective, consider the Barr Trail, which ascends Pikes Peak in Colorado Springs, Colorado, says Amie Dworecki, head running coach at Running With Life in South Bend, Indiana. It has an average incline of 11%, “so, the 12-3-30 workout is similar to suddenly starting to walk up a mountain without breaks,” she says.

If you’re new to exercise, don’t have a walking routine or are living with a chronic condition like heart disease, the 12-3-30 workout may not be safe for you, says Dworecki. Even if you’re in shape, starting any form of vigorous exercise and doing it as many days as you can could set you up for overuse injuries like shin splints, plantar fasciitis or sore knees.

For these reasons, it’s best to gradually build up to this level of intensity and check in with a healthcare provider if you have any questions or concerns about your capacity to tackle it.

When you walk on such a high incline setting, you’re engaging more of your glute and hamstring muscles as you work against gravity. That makes for more of a cardio challenge, says Meghan Kennihan, a USA Track & Field certified running coach. This also comes with more calorie burn than walking on flat ground. In this sense, adding the 12-3-30 workout to your routine could potentially help you slim down.

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But when you’re trying to lose weight, your diet is often even more important than exercise, says Dworecki. “While Giraldo’s plan of just doing this exercise alone without watching what she eats may work for her to lose weight, it may make other people more hungry, causing them to eat more,” she notes. In fact, the belief that exercise on its own can lead to weight loss is one of the most common weight-loss myths that could lead you to overestimate how many calories you’re actually burning at the gym.

Warming up to the 12-3-30 workout is key, so aim to be able to walk for 60 minutes at least four times a week or 30 minutes a day for 2–3 weeks without trouble before attempting it, says Kennihan. Then, slowly turn up to a higher incline (Think: 1 minute at 2%, then 4%, 6%, and more). If that’s too tough, try cycling between intervals such as 30–60 seconds at 3–4% and 0% until you’re comfortable enough to level up, suggests Dworecki.

Ideally, you want to use and develop different muscle groups to get fit and avoid injury. So instead of doing the 12-3-30 workout over and over again, make sure to mix up your routine with other forms of cardio, strength training and workouts to improve flexibility like yoga.

“The 12-3-30 treadmill workout is a great way to get a vigorous cardio workout without the impact of running, and it makes treadmills a little more interesting,” says Kennihan. “However, it’s not a magic pill for weight loss or getting in shape.”

To lose weight, a multipronged approach is key, so don’t ditch essential elements of the weight-loss equation for a fad workout. A consultation with a healthcare provider, plus a healthy diet, stress management, self-care, frequent movement and quality sleep helps fuel sustainable weight-loss success.

For more fitness inspiration, check out “Workout Routines” in the app to discover and log a wide variety of routines by performance specialists. Or build your own routine with exercises that fit your goals.