What a Personal Trainer Really Thinks of the Viral TikTok “12-3-30” Workout

published Dec 13, 2022
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Woman walking on treadmill in living room at home
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It’s hard not to be skeptical toward trendy workouts, especially when mainstream culture tends to treat wellness and weight loss as synonyms. But just because something is super popular doesn’t necessarily guarantee it’s nonsense. 

If you’ve been anywhere on social media in the last few years, you might’ve heard of the 12-3-30 workout. If not, some background: Influencer Lauren Giraldo created a treadmill workout that she called the 12-3-30, which she shared on YouTube back in 2019; it took off when she shared it again on TikTok in 2020. It’s very straightforward — get on the treadmill and set the incline to 12. Then walk at three miles an hour for 30 minutes. 

Giraldo says it made her feel more confident about going to the gym, and that she lost 30 pounds doing exclusively this workout five days a week. If you scroll through comments you’ll see plenty of 12-3-30 praise and endorsements from those who have experienced similar results. 

Clearly it’s popular, but is it a good workout? I decided to ask my trainer, Jessica Burdick, who’s a powerlifting coach and the owner of JBurdie Fitness in Boston. And since we’re thorough, we both decided to try it for ourselves.

Is it a good workout?

Gym intimidation is real, and any movement is a good thing. So if this is the workout that makes you comfortable moving more, that makes it a good workout.

“It’s easy to digest. That’s what makes it TikTok friendly, right? I like the way Lauren framed it — that it was a way to get her into the gym. It has a low intimidation factor,” says Burdick. “It’s very accessible in the sense that you could have a $10 gym membership to a Planet Fitness and do this, which is great.”

The workout centers around walking, which is considered a low-impact exercise. There are plenty of benefits to low-impact exercise, including improving balance and heart health, while decreasing blood sugar levels, blood pressure, and LDL (“bad”) cholesterol. Plus if you do 12-3-30 five times a week like Giraldo, you’re hitting 150 minutes a week, which is the American Heart Association’s recommendation for physical activity.

Are there drawbacks?

To be clear, this isn’t exactly a chill workout. Burdick and I both lift three to four days a week, and I can swim about a mile straight comfortably (which is cardio, for reference), so we’re both in decent shape — and let me tell you, we felt it. 

“It’s really hard. The incline was intense on my back and my ankles because of the flexion, so if you have tight calves or ankles the 12 percent incline would be intense,” says Burdick. “I’d consider myself physically fit, and I wanted to turn the incline down.”

I also worry that someone already feeling intimidated by the gym would be discouraged by this workout if they’re starting from a more sedentary place. “Three miles an hour was good, but 30 minutes is a long time,” Burdick agrees. “You could also break that up into a seven day span and do 20 minutes every day. Or even if you’re about to weight train, you could do 10 minutes to warm up.”

Will I lose weight? 

Again, weight loss and better health aren’t synonymous, and the 12-3-30 workout isn’t a magic formula for losing weight. If you start doing this workout five times a week like Giraldo when you formerly weren’t active, it could likely lead to a calorie deficit which would cause weight loss. But weight loss can also be impacted by a myriad of other factors like your genetics, the type of medication you take, or how much muscle is on your body. 

“Basically yes, if you do this workout you could lose weight. But there are nuances,” says Burdick. “For example, I burn more calories than someone who doesn’t strength train. Let’s say that they do cardio — the second they’re done doing cardio, they’re done burning. When strength training, your body creates micro tears in your muscles and needs to regenerate those muscles, which continues to require energy and burn calories.”


The important thing about this workout is that it’s motivated people to include more movement in their life, which, I love to see it. If you’re thinking of trying 12-3-30 for yourself, consider sparing yourself from having tight calves by slowly increasing the incline as opposed to starting at 12 percent out of the gate. If