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It’s too hard for many people, yet still not enough for a full workout routine.

November 3, 2025

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The 12-3-30 workout has taken over TikTok, which is a testament to the algorithm and a few influencers’ abilities to game it. It’s really just treadmill walking, with specific parameters and overblown promises. So let’s break down the pros, cons, and caveats—and make a plan for how to do a similar workout that makes sense for you.

What is the 12-3-30 workout?

It’s walking on a treadmill with the incline maxed out. In other words, you’ll be walking uphill. You set the incline to 12% (the highest you can go on many treadmills), the speed to 3.0 miles per hour (a pretty typical walking speed for most of us on flat ground) and you do it for 30 minutes.

Its popularizer, Lauren Giraldo, has said she does it five times a week. She has also said it’s the main thing she does in the gym, with other exercises thrown in less consistently, and she has shared before-and-after photos of other women who credit the workout with helping them lose weight.

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Is the 12-3-30 workout good for weight loss?

Trick question! No individual workout is going to be responsible for weight loss. You lose weight by eating slightly less than you burn, measured as an average over time. Exercise can help you burn more calories, but your body often compensates by burning fewer calories when you’re at rest, so you can’t just trust a treadmill walk to burn a certain number of calories each time.

To try to find out whether 12-3-30 is better at weight loss than other types of treadmill workouts, this study compared results from people who did the 12-3-30 to people who did their own self-guided treadmill workouts. They matched these workouts on calorie burn, so that the question was not “which burns more calories?” but rather “what are the pros and cons of using this workout to burn a certain number of calories?”

The good news for fans of 12-3-30 is that it burned a slightly higher percentage of calories from fat. But this is arguably the least important part of a weight-loss workout, since your body is constantly storing and burning fat, storing and burning, throughout the day. What matters is total fat loss or total calorie burn over the long term. So I wouldn’t make decisions based on this data point.

There was bad news, too: The 12-3-30 took longer to burn the same amount of calories as a self-guided treadmill workout. The researchers concluded that if you want to burn your calories efficiently, you should do a treadmill run rather than 12-3-30. And if you want to burn the greatest percentage of your calories from fat, you should do an easier workout, reducing the incline and staying on the treadmill even longer.

Is the 12-3-10 workout appropriate for beginners?

Look, this workout is hard. It’s often suggested for beginners, but if you’re not used to uphill walking, your calves will be burning and you’ll be gasping for air in the first few minutes. Giraldo herself says she was out of breath after two minutes the first time she tried it, and she told Today that at first she had to stop and rest after the first 10 or 15 minutes.

If you haven’t done any treadmill walking, let’s take a little tour through the numbers. Three miles per hour is a pretty normal pace for walking on flat ground; if you ask Google Maps for walking directions to a place that’s a mile away, it will estimate that you’ll take 20 minutes to get there, which is three miles per hour. So that part is pretty reasonable.

But then you start bumping up the incline, and everything changes. A 1% incline is noticeably harder than walking on flat ground. 2% is already pretty steep. Keep hitting that “increase incline” button and by the time you hit 12% it’s going to be ridiculous. (For comparison, riding lawnmowers aren’t usually recommended for a 15% slope. Imagine looking at a hill and thinking “hmm, I don’t know if I can mow that safely,” and that’s pretty close to what you’re aiming for here.)

An incline that steep will be a cardio challenge, and it will probably make your muscles sore the first time, too. (Think calves, hamstrings, butt, and quads. Maybe your back, too.) If this is challenging for your muscles, you probably shouldn’t do this for 30 minutes your first time, and you definitely shouldn’t repeat it four more times that week.

Is the 12-3-30 workout so good you don’t need strength training?

Nope. Once your body gets used to this workout, it is cardio. Cardio is very, very good for you, but it’s not the same thing as resistance training, which is the other essential component of an exercise routine.

So if you want to do this and your body is up for it, great! Just make sure to add a strength training program before, after, or instead of your treadmill walk on at least two days of the week.

What do you think so far?

What the 12-3-30 workout gets right

First, inclined treadmill walking really is a great alternative to running. Find a speed and incline that get you breathing just a little bit harder than at rest (not out of breath), and your heart and lungs will be working about as hard as if you were jogging at an easy pace. If you hate running, but want to use a treadmill as your main cardio machine, incline walking is a great option.

Secondly, it’s simple. It’s attractive to beginners because you know exactly where you’ll go in the gym and what settings you’ll punch in. That breaks down a ton of the barriers people often have when they’re starting a new exercise program. Just go in, and do it.

And finally, if you stick to the schedule—30 minutes, five times a week—you’ll exactly meet the U.S. and World Health Organization exercise recommendations, which call for a minimum of 150 minutes of cardio per week (alongside at least two days of strength training).

What to do instead of the 12-3-30 workout

If you like the idea of a simple treadmill workout to get in your cardio for the day, you can do that—but you don’t need to start with 12-3-30. Exercise routines are not one-size-fits-all, and you need to find the workout that makes sense for you.

So, start by finding a speed on the treadmill where you can walk for at least 20 minutes. If you need to take breaks, or if you can’t manage a whole 20 minutes at first, that’s fine. Set the speed to 3.0 (or less if you need to), and work toward a goal of 20 minutes. Once you can get 20, extend it to 30. If you’re out of shape to start with, this whole process may take a few weeks.

In the meantime, work on your consistency. Can you exercise three times a week? Again, start with whatever you can do, and add onto it. Now you’re at 0-3-30, and doing this three times a week. Maybe this is enough for now.

When you’re ready for more of a challenge, start increasing the incline. Can you still make it 30 minutes if the incline is set to 1%? How about 2%? You get the idea: Use the most challenging setting that allows you to get off the treadmill feeling like you’ve done a good workout, and like you’re ready to do it all again tomorrow. It doesn’t matter if the incline is 1% or 12%. And if you hate treadmill walking, there’s nothing magical about it—you can hop on an elliptical or spin bike instead.

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