I used to be in a long-term love/hate relationship with the treadmill. I loved the runner’s high that set in any time I pushed my body farther and faster than I thought it could handle, but I hated how easily that feeling (and the numbers game that inevitably came along with it) could push my behavior into disordered territory.
So a few years ago, I decided to break up with the treadmill for good. In the process, I learned how to listen to my body, and committed exclusively to workouts that brought me joy.
Then last month, on a morning when I was in dire need of a good, stress-relieving sweat, I found myself in a hotel gym with a high-tech version of my old frenemy that looked very appealing. To be perfectly honest, I didn’t trust myself to get on it and go for a run—old habits die hard, and I was worried about ruining my vacation with the type of toxic “MUST RUN FASTER!!!” thoughts that used to dominate my exercise routine. Instead, I decided to try out the 12-3-30 workout that’s dominated my social feeds for the better part of the past six months.
What is the 12-3-30 workout?
The buzzy, low-impact workout first emerged in late 2020 via a TikTok video shared by Lauren Giraldo (which, to date, has garnered 12.7 million views and 2.8 million likes). It involves walking on a treadmill at a 12 percent incline and 3 mile per hour pace for a total of 30 minutes, and it promises to deliver a double dose of cardio and strength training benefits.
“There are benefits to elevating the treadmill incline, including improved cardiovascular function, higher caloric burn, and glute strengthening,” Holly Roser, a personal trainer and owner of Holly Roser Fitness, previously told Well+Good. “This is the best possible form of cardio outside of running, as you’re using your entire body. That’s unlike when you’re on a bike or elliptical, where the machine is helping your movement, causing less effort on your part. It’s also low-impact, which is easier on your joints—especially for those who are having knee pain or low back pain.”
Considering my old treadmill workouts used to involve running as fast as I could for as long as I could, I assumed that a walking workout would be an easy, breezy way to close the rings on my Apple Watch. Boy, was I wrong.
What happened when I tried it
That first morning, I hopped on the treadmill, queued up the first episode of Emily in Paris season 3, cranked up the incline, and got moving.
Within the first five minutes, I was drenched in sweat, and by minute 13, I swear I could actually feel the muscles in my butt and legs getting stronger. I quickly learned that in order to maintain proper form and avoid discomfort in my lower back, I had to engage my core and keep my shoulders back, which meant I was getting a little extra practice in the posture-improvement department. What’s more, when I looked at my heart rate tracker, I was shocked to see that the numbers were comparable to what they are during a dance cardio class.
As I walked, a weird thing happened: I didn’t feel like I had to push myself any harder than I was already going, which was a major fear of mine when I stepped onto the treadmill in the first place. I didn’t have to play with the speed or incline or worry about anything except for putting one foot in front of the other. I could simply turn off my brain, watch Emily Cooper butcher the French language, and enjoy the movement—which is something I’d never in my life experienced on a treadmill.
I loved the experience so much that I decided to swap in 12-3-30 for the rest of my weekly workouts—which meant doing it four times a week for two straight weeks (and, okay, doing it two more times so I could finish the season and see if Emily chose Alfie or Gabriel). The practice became sort of like my daily meditation. It allowed me to clear my mind, which does not come naturally to me, like, at all. The regular endorphins boost the workout delivered was an added bonus. (Though the second-day soreness in my legs every single day during the experiment was… not.)
Now that I’m back in my regular routine, I’ve started to mix 12-3-30 walks in with my usual HIIT and yoga class lineup, and it’s become one of my favorite ways to start the day. (I did a session just this morning and realized that both of the women on the treadmills next to me were doing the exact same thing.) It’s the perfect way to shut off my brain before diving into whatever madness will inevitably come when I open my email, and I’ve found that it actually helps with my focus throughout the day.
Dozens of 12-3-30 sessions later, my legs feel stronger and two of my friends independently asked me why my butt has looked “extra juicy” recently. But that isn’t what’s kept me going back for more. I love that I’ve reunited with the treadmill in a way that feels great for my mind and my body, and that gets me dripping with sweat in the process. And, okay—the “juicy butt” thing doesn’t hurt, either.