I Tried the 12-3-30 Workout. Here's Why I Won't Do It 5 Days a Week Again.

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I tried it 12-3-30 workout composite

Verywell / Michela Buttignol

Key Takeaways

  • The viral 12-3-30 workout involves walking on a treadmill at an incline of 12 and speed of 3 for 30 minutes.
  • Walking on an incline can offer aerobic benefits and add variety to a fitness routine.
  • The steep incline presents a risk for lower extremity injuries.

I’ve been a runner for as long as I can remember, but after completing the NYC marathon last November, I’ve been looking for a way to break up my fitness routine.

Crossing the finish line in Central Park was a life goal of mine, but the training took a mental toll. Running started feeling like a chore instead of a release. With the marathon behind me, I looked for other ways to move my body—including barre and trampoline workouts—so when my editor asked if I wanted to try out a new TikTok 12-3-30 workout, I jumped at the opportunity.

Lauren Giraldo, the TikTok influencer behind the 12-3-30 trend, first posted about it on YouTube in 2019 and on TikTok a year later. She said this workout has helped her lose 30 pounds without dieting or counting calories. While Giraldo is not a certified trainer, she has inspired a community of people who want to stay fit by walking and even hosts in-person "hot girl walks."

If you, like me, are new to this workout, here are the basics:

  • Set the treadmill to an incline of 12
  • Put the speed on 3
  • Walk for 30 minutes

That's it. Giraldo recommends doing this straightforward workout "as many times as you can a week" but said she aims for about five times a week—so that became my goal, too.

Walking at a Steep Incline Isn't Exactly Easy

Walking, like other forms of physical activity, offers tons of health benefits. It can help reduce stress and lower the risk of developing chronic disease. And walking on an incline—without increasing your speed—can help you meet the recommendation of 150 minutes of moderate-intensity physical activity each week.

I’m a morning workout person, so I decided to do 12-3-30 before breakfast. My apartment building has a gym, so I got ready on a Sunday morning and went downstairs for the first day of my new routine.

Right away the incline felt steeper than I expected. My usual running route is very flat, so an incline of 12 was noticeable.

Once I got going, I wasn’t out of breath, but my heart rate was elevated. I even read a book on my Kindle app, which made it feel more relaxing than any other workout I’m used to.

The next morning, I returned to the gym and my trusty treadmill. However, on day three, I started to notice some lower back pain. 

Christopher J. Lundstrom, PhD, a professor in sports and exercise science at the University of Minnesota, told me that he has some concerns over the incline. “12% is pretty substantial," he said.

He said that walking at this incline can put a lot of stress on the lower limbs and it’s not a workout he would recommend doing every day.

Being a stubborn athlete, I wasn’t going to let some minor pain keep me from finishing my workout plan. I hopped on the treadmill for the next two days to finish my 12-3-30 challenge.

But even as I’m writing this now, I can feel a nagging pain in my lower back. 

“Starting at a lower incline and shorter increments, and building up from there might be a safer way and healthier way to implement it,” Lundstrom said.

The Outcome

I was eager to try 12-3-30 to get out of my running rut, but doing this five days a week was too much for me. 

“With any kind of fitness trend, the message that this one thing is all you have to do, and that's going to change everything for you, is always a bit of a red flag,” Lundstrom said.

Trying this workout was a good reminder that I need to listen to both my mind and my body when it comes to my workouts. Training for the marathon left me craving a balanced fitness routine so jumping into a five-day-a-week treadmill workout doesn’t feel right. 

Doing 12-3-30 the same day as another workout probably isn’t the best idea for me either. I did a 30-minute rowing workout on day 1 and a 4-mile run on day 3, which could have added to the back pain.

While this won’t become a go-to for me, mixing in a 12-3-30 workout once a week could offer some much-needed variety. This challenge was a good reminder that I can find different ways to move my body when I need to shake up my running routine.

Want to Try It Yourself?

If you want to give the 12-3-30 workout a try, all you really need is a treadmill that can safely incline to the proper height and a pair of walking or running shoes. When choosing a treadmill, it's important to look for one with a range of speeds and inclines and an easy-to-use dashboard to help you program your settings. Nice-to-have features include memory settings that will allow you to save inclines and speeds (like the 12-3-30 workout) so you don't have to set it up every time you want to hit the belt. Here are some of the best treadmills with incline and speed settings to help you get started:

The Final Verdict

Variety in your fitness routine is key. Doing any repetitive workout five days a week is mentally and physically taxing. When I'm not training for a race, I want to mix up my workouts and maybe that means adding in a 12-3-30 workout every now and then.

1 Source
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  1. U.S. Department of Health and Human Services. Physical Activity Guidelines for Americans - 2nd Edition. U.S. Department of Health and Human Services; 2018.