What Is the 12-3-30 Workout, and Why Is Everyone (Still) Obsessed?

When I first heard about 12-3-30 — the name of the viral 30-minute treadmill incline workout taking the internet by storm — I was only mildly intrigued. TikTok has introduced us to so many exercise buzzwords throughout the years, only a few of which have actually stuck (shoutout to you, hot girl walks). Typically, my preferred cardio involves walking my dogs in the woods. But there are times when the weather doesn't cooperate, and it would be nice to have another go-to indoor option. Enter, 12-3-30.

In essence, 12-3-30 is a simple and walkable alternative to high-intensity cardio, helping people stay motivated and consistent with their workouts. It sounds easy enough in theory, but gym-goers swear it's actually a challenge. "It is way harder than it sounds," says content creator Ava Vescovi in a video documenting her 12-3-30 before and after. "Trust me, you'll be dripping sweat by the end." Given all the hype about the 12-3-30 workout and 12-3-30 results (including transformation videos with millions of views on social media), I decided to see how well the treadmill incline workout held up IRL. Here's what happened after trying the 12-3-30 treadmill workout for myself.

Experts Featured in This Article:

Nicole Rodriguez is a registered dietitian and NASM-certified personal trainer.

What is the 12-3-30 Workout?

12-3-30 is a 30-minute treadmill incline workout where the incline is set to 12 percent and the pace is set to three miles per hour. It's really that simple. Influencer Lauren Giraldo first introduced the 12-3-30 workout on YouTube in 2019, but it didn't become popular until Giraldo posted a TikTok about it in late 2020, crediting it for helping her lose weight and keep it off for years.

The workout has since gone viral, but it's also withstood the test of time. On social media, people are still calling themselves "12-3-30 girlies" and sharing their love for the workout, including their 12-3-30 results and any modifications. From the outside looking in, 12-3-30 may seem like an unassuming cardio routine, but it's definitely fostered a sense of community and helped cardio feel less intimidating for many.

12-3-30 Workout Benefits

12-3-30 is incredibly straightforward — no interval timers or complicated instructions required. It's a challenging yet low-impact workout that makes cardio a little less painful, and it comes with plenty of benefits. Here are some of the most notable:

12-3-30 Workout Risks

All workouts come with some level of risk, and the 12-3-30 workout is no different. "I would deem this safe with physician's clearance," Rodriguez says. That said, if you're struggling with knee pain or injuries of any kind, this workout may not be right for you. To help prevent injury while incline walking, maintain good posture, engage your core, and avoid slumping forward or leaning your weight onto the handrails of the treadmill.

Additionally, the 2012 study found that adding an incline changes your walking gait. That means if you're a beginner to steep incline workouts, you should go slowly in order to avoid injury or muscle strain. Doing too much too soon can put you at risk of an overuse injury (when tissue is damaged due to repetitive demand), according to the Hospital for Special Surgery. It's best to gradually build up the incline and speed at your own pace.

12-3-30 Workout Results

After hearing all the hype, I decided to try the 12-3-30 workout for two weeks to see how it compared to my usual workouts (including HIIT, running, and rowing). I did the 12-3-30 method five times a week, per Giraldo's recommendation — read on to learn about my results.

— Additional reporting by Lauren Mazzo and Chandler Plante