Long after its creation (in social media trend time), the 12-3-30 workout is still a topic of conversation in the fitness space. I’ve been asked about it repeatedly and written about my thoughts on this trend several times. But if this is the first time you are hearing of it, let me give you the rundown.
12-3-30 is a treadmill workout with its prescription right in the name. Set your treadmill to an incline of 12% and a speed of 3 miles per hour, and then walk for 30 minutes. While I have various recommendations to make the workout harder or easier, that’s the original workout.
Now that 12-3-30 has been around long enough, researchers have published a study on how it compares to treadmill running. In this blog post, I’m going to summarize the study and give my thoughts as an exercise physiologist.
What Does the Research Say
I’m always excited to read new research. I’m a certified exercise physiologist with a master’s in biomechanics, so I love to see fitness advice grounded in science. Now, we have a research study from the University of Nevada, Las Vegas on the 12-3-30 treadmill workout.
Researchers pitted treadmill running against 12-3-30. Participants completed two workout sessions. The first was the standard 12-3-30 workout. During this workout, the researchers measured participants’ energy expenditure (how many calories they burned).
Days later, participants returned to complete a treadmill running workout at the speed of their choosing. Researchers allowed the participants to adjust their speed during the workout whenever they liked, as long as they stayed at a run instead of a walk. The workout was over when the participants expended the same amount of energy as they did during the 12-3-30 workout.
Results
When researchers compared the results of the two workout sessions, they found that the treadmill running sessions took less time (about 24 minutes) to reach the same calorie burn as the 12-3-30 workout. While this result suggests your time is better spent running, there are other factors to consider.
Both workouts caused the participants to use more carbohydrates than fat for fuel, but the percentage of fat was higher in the 12-3-30 workout. This result does not mean that the 12-3-30 is better for weight loss, as calorie burn is more important.
Researchers also pointed out that both workouts may be too intense for exercisers who are trying to target fat utilization, since participants mostly used carbohydrates. If you are exercising in a fasted state, targeting fat utilization is important, as you do not have adequate carbohydrate stores to fuel higher-intensity exercise. If you train at a higher intensity, you may end up using a higher amount of protein for fuel.
Advice from an Expert
Now, before you start trashing the 12-3-30 workout because it takes more time to burn the same number of calories as treadmill running (at a self-selected pace), hear me out. I think the 12-3-30 is still an excellent option. While researchers were correct that there is a statistically significant time difference between the two workouts, it may not be significant to you.
If you hate running and enjoy the 12-3-30 workout, then I think it’s a good tradeoff to do 12-3-30 instead of running for 25 minutes or so. Trying to force yourself to do a workout you dislike could come back to bite you. You may waste those extra minutes you save running by dragging your feet to the workout. You may miss more scheduled sessions.
In the long run, choosing a type of cardio that you enjoy is best. You will be more motivated and skip fewer sessions, which leads to more calories burned!
Why You Should Still Choose 12-3-30

I’m a runner, and I love it, but there are several other reasons you might want to still choose 12-3-30 over treadmill running.
It’s low impact. Adding a steep incline to a walking routine increases your calorie burn while keeping your exercise low-impact. Runners have high rates of injury (trust me, I know firsthand, and walking may be better for weight loss because you won’t get sidelined by the effects of those high forces.
It’s beginner-friendly. I’ve run three marathons, one ultra, and well over 10,000 miles in my lifetime. Yesterday, I stopped to take a break 20 minutes into my run. Running is hard, and just because some people can run for 25 minutes straight doesn’t mean that’s appropriate for your fitness level. 12-3-30 may be more feasible for you, and there’s nothing wrong with that.
You feel a part of something. I love that running makes me part of a community, but I’ve heard from many runners that they feel unwelcome. 12-3-30 is a popular TikTok trend, and posting about completing the workout may be an important part of your journey. If that’s your community and not a run group, that’s an important step in your weight loss and fitness journey.
You can add weight. Sure, people run with weighted vests on, but carrying a hydration pack that was too heavy almost sidelined my husband from his last ultra due to knee pain. Walking with a pack on, even on an incline, is lower impact and much more doable for a lot of people. Then, you’ll be burning even more calories.
Not all treadmills are great for running. Some treadmills are great for incline training but are not ideal for regular running. If you have a smaller walking treadmill, 12-3-30 might be a better option. Even if your treadmill can go fast enough to allow running, sometimes the deck is too short. Incline training is an excellent alternative.
When to Choose Running on the Treadmill Over 12-3-30

Most days, I’m choosing treadmill running over 12-3-30.
I have a 25-minute run scheduled for the very day that I’m writing this. I’m not even considering switching it to 12-3-30 for the same calorie burn. I am building my base back up for marathon training, and I love running.
Here are some reasons you might choose treadmill running over 12-3-30, too:
You’re a runner at heart. If you enjoy running or want to train for a race, a treadmill running workout will bring you closer to your goals.
You are short on time. You stepped out from work on your lunch break to get a quick workout in to progress your weight loss. Going for a run on the treadmill gives you more bang for your buck than 12-3-30.
Your treadmill doesn’t incline. Add speed if you can’t add incline.
You’ve already done 12-3-30 this week. No one said you can’t do both. Try running on higher intensity days and save 12-3-30 when your legs need a break from the impact.
You hate cardio and want it to be over ASAP. If doing 12-3-30 or running for 25 minutes sounds equally horrible, but you don’t have a third option, go for a run. It will be over sooner for the same calorie burn.
Conclusion
Many of us do not have easy access to health and fitness research. Even if we do, it may be difficult to understand and interpret. Sometimes researchers are focused on things we just don’t care about. It’s nice to see research investigate a social media trend and give us actionable advice that we can use to inform our exercise routines.
Whether I’ve convinced you to try 12-3-30 or crank up the speed for a run, I hope you feel like you can plan your next exercise session feeling confident in tackling your goals. Knowing why we should choose one activity over another helps us make the most of our time.
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