What Is the Viral 12-3-30 Workout?

So, I’m a little late to the party on the 12-3-30 workout.

I live under a rock called motherhood, and I’m admittedly more of a Peloton girly when it comes to cardio. But, I also need to switch up my routine pretty often so I don’t get bored. So when Cassey posted about trying this treadmill workout, I needed to know more.

What is the 12-3-30 workout?

Coined in 2019 by Lauren Giraldo, the 12-3-30 treadmill workout gives a good cardio burn like a run, without having to actually run. Her video about the workout and how it changed her body went viral, eventually catching the attention of celebs like Kylie Jenner. NBD, right!?

Here’s the setup:

  • 12% incline
  • 3 mph
  • 30 minutes


You can do this workout on any treadmill that has an incline function! If you don’t have a treadmill, I’ve seen variations for an elliptical. You could also take the gist of this and walk some hills outside.

cassey ho treadmill workout

K, but what’s the 12-3-30 hype?

The way this workout gets your heart rate up is sneaky! You’re “just” walking, right? Wrong.

When Cassey tried it out for the first time, she noted that her heart rate was around 145 beats per minute (bpm), which she said was higher than it gets on runs sometimes.

It’s the incline that makes your heart work harder. Although 3 mph is a doable pace for most, the incline makes it more like hiking uphill at this pace, for 30 minutes. Your heart is definitely getting a workout.

Increasing your heart rate is a great way to strengthen your heart, which can help lower blood pressure and cholesterol. Putting in the cardio work can also lower your resting heart rate, which generally means better cardiovascular fitness.

Your muscles will feel it too

I mean, your muscles are working when you walk a flat road. But during a 12-3-30, the incline works as resistance. Just imagine walking a decently steep hill for 30 minutes with no breaks and you can kind of feel the work your legs are about to endure.

That resistance will help strengthen mainly your calves, hamstrings, and glutes, which aren’t targeted as much when you walk on zero incline.

What you won’t feel as much is joint pain. Walking at an incline is lower impact than running, which means it’s easier on your joints.

You’ll get a good calorie burn

This makes sense, right? Your heart is working harder and you’re using more muscles, so you burn more calories! The metabolic equivalent of this workout could be close to actually jogging, which is cool! But also keep in mind that there are plenty of workouts that can give you that same burn, if this one isn’t for you!

Plus I feel like this is a good time to say that walking, even without an incline, is an amazing workout. This article by one of the Blogilates designers inspired (read: influenced) me to try an under desk treadmill while I work. I’m a few months in and LOVING it.

It boosts your mood

We love to see it.

Regular exercise improves your mood and stress levels, period. Sometimes the key is just finding the right workout that you enjoy enough to do consistently! The 12-3-30 might be the one.

Give it a shot!

12-3-30 is a great alternative for people who hate running but still enjoy a challenge on the treadmill. Or people like me who just need some variety… maybe while watching your fave show or finally finishing that audiobook?

If you give it a try, start slow and work your way up! A lot of people are surprised at just how challenging it is to hold a 3 mph pace at such a steep incline 30 minutes. After you do it a few times, it will feel easier (ahem, you will be STRONGER!)

And as always, make sure your healthcare provider is cool with you trying something new.

30 minutes and done

This is a great workout if you’re like me, telling yourself to “just do 5 minutes” because you know starting is the hardest part. Before you know it, 30 minutes will be up.

Just be ready to sweat.

If you try it or weren’t late to this treadmill party like I was, comment what you think and if you can do the whole thing without holding on 👀

2 thoughts on “What Is the Viral 12-3-30 Workout?”

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  1. Allyson says:

    I gave this a shot at the gym last week. I actually kind of liked it! It’s not going to be an everyday thing for me, but I will keep it in my cardio routine. I was surprised by how much sweat I got. But no, I cannot yet do it without holding on!!

  2. Theresa Ladd says:

    I love this challenge! I am on day 19 and I look forward to it every morning. I have to admit I do hold on- for dear life! I hate hiking and hills of any kind so this was a big personal challenge. My new goal each day is to hold on a minute less; so far so good! On a side note, I have been doing the pelaton and my legs and butt feel better in a shorter amount of time on the 12-3-30 challenge.