When I first heard about the 12-3-30 workout — an incline walking workout you do on a treadmill — I was only mildly intrigued. I prefer walking in the quiet, hilly woods near my house with my dogs since it’s a great workout and essential for my mental health. But sometimes the weather doesn’t cooperate, so the 12-3-30 workout seemed a great indoor workout option.
Not to mention, it’s all over social media: videos captioned with 12-3-30 have raked up nearly 135 million views on TikTok alone. So I also wanted to see what all the fuss was about.
What Is the 12-3-30 Workout?
The 12-3-30 workout is a treadmill workout where you set the incline to 12 percent, the pace to three miles per hour, and you walk for 30 minutes. Yes, it’s 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 30 pounds and keep it off for two years. The workout has since gone viral — and stuck around for years. People all over social media call are calling themselves “12-3-30 girlies” or “12-3-30 babes” — sharing their love for the workout, how they’ve modified it, and also their 12-3-30 results.
12-3-30 Workout Benefits
Social media users love the workout because it’s straightforward — no interval timer or further instruction needed — and because it offers a challenging yet low-impact way to get in some cardio. That’s right: the 12-3-30 treadmill routine is great for your cardiovascular health, as it gets your heart rate up as much as going for a jog, without the impact on your joints. In fact, research shows that incline walking may even help strengthen the knee joints.
The steep, 12-percent incline makes your body to work harder than walking on a flat surface, explains registered dietitian and NASM-certified personal trainer Nicole Rodriguez. This places more demand on your body, forcing it to expend more energy and getting your heart rate up. For example, a small 2015 study found that the metabolic cost (aka calorie burn) of walking increased by 17 percent when set at a 5-percent incline, and by 32 percent when set at a 10-percent incline when compared to walking on flat ground.
The 12-3-30 workout also has muscle-building benefits: that same 2015 study found that incline walking increases activation in many of the muscles in the lower body compared to walking on flat ground. Specifically, walking on an incline strengthens your glutes, quadriceps, hamstrings, and calves more than walking on a flat surface.
12-3-30 Workout Risks
All workouts come with some level of injury risk, and the 12-3-30 workout is no different. “I would deem this safe with physician’s clearance,” Rodriguez says, but if you’re struggling with knee pain or injuries of any kind, this workout may not be right for you — and that’s OK!
To help prevent injury while incline walking, experts at Texas Health recommend keeping your posture in mind: stand up tall, engage your core, and avoid slumping forward or leaning your weight onto the handrails.
The 2015 study found that adding an incline changes your walking gait, so your muscles may not be ready for this movement if it’s new to you. If you’re new to steep-incline walking workouts, you should ease into it to avoid injury or strain on your muscles. Doing too much too soon can put you at risk of an overuse injury (when tissue is damaged due to repetitive demand over a period of time), according to the Hospital for Special Surgery. It’s best to gradually build up the incline, speed, and time as you’re ready, taking several weeks or months if you need.
What Happened When I Tried the 12-3-30 Workout
I decided to try the 12-3-30 workout for two weeks, doing the workout five times a week, per Giraldo’s recommendation. I wanted to see how this walking workout compared to the HIIT workouts, running, and rowing I’d been doing in the past few months. Could a walking workout really be as effective? Keep reading to hear about my 12-3-30 workout results.
— Additional reporting by Lauren Mazzo