As a veteran personal trainer and gym owner, I usually don’t look to TikTok for workout program ideas. However, the overwhelming popularity of the 12-3-30 workout recently caught my attention. With so many of my clients asking about it, I decided to do a deep dive and find out just how effective 12-3-30 is for weight loss.
What is the 12-3-30 Workout?
The 12-3-30 workout is the creation of social media influencer Lauren Giraldo. Like many people, Lauren felt quite intimidated and unsure of what to do at the gym. So, she decided to zero in on the treadmill and follow a simple formula that she knew she could stick to.
Lauren’s plan had three parts:
- Set the treadmill incline to a 12% incline.
- Set the speed to 3 miles per hour.
- Walk for 30 minutes.
Lauren started this program in 2019. Within a few months, she’d lost 30 pounds and looked and felt great. Her success inspired her to post a video on YouTube, which got a lot of attention.
In 2020, Lauren decided to post a 37-second video about her 12-3-30 treadmill workout on TikTok. And that’s when the magic happened. The clip now has millions of views, and people all over the world have jumped into the program.
What’s So Good About the 12-3-30 Workout?
The 12-3-30 workout has clearly caught on in the gym-going public’s imagination. A key reason is its simplicity. It involves just one exercise and three numbers — 12%, at 3 miles per hour for 30 minutes.
That is a big deal for people intimidated by the whole gym scene. The 12-3-30 workout program is straightforward, requiring no new exercise techniques, no memorization of unfamiliar exercises, and no need to watch yourself in the mirror. Just get on the treadmill, blast your favorite music, and start walking.
If you’ve tried this workout, you know that simple doesn’t mean easy. Even though three miles per hour is a walking pace, doing it at a 12% incline is challenging. It will put tension on your glutes, hamstrings, and quads, so expect a pretty good leg burn at the end of it.
Another benefit of the 12-3-30 workout is that it’s low impact. Because you’re not running, the ankle, knee, and hip joints have a reduced jarring effect. Add in the underfoot cushioning you get on modern treadmills, and it’s good news for people with joint problems.
A huge factor that makes 12-3-30 so attractive is its accessibility. Many newcomers are intimidated by new and different exercises that they perceive as being beyond their capability. But we all know how to walk, and three miles per hour is the average walking pace for most adults.
This walking pace helps overcome a psychological barrier for some people.
The social media aspect of this workout adds yet another positive element. Over the past few years, many people have backed the 12-3-30 workout. You’re bound to be able to find a group of fellow exercisers who will support you in your journey.
Benefits of Treadmill Walking
Walking on a treadmill may seem mundane, especially compared to some of the more recent cardio training innovations. Yet, there are a lot of benefits to come from getting into the treadmill habit. Here are five of them:
- Convenience: Finding the time to walk outdoors can be challenging. Bad weather and safety are other issues that you may have to consider. You don’t have to worry about any of those issues with a treadmill.
- Precision: When you do your walking workout on a treadmill, you can precisely monitor your speed, incline, heart rate, and calories burned. That allows you to customize your training to fit with training protocols like the 12-3-30 workout.
- Low impact: Modern treadmills have advanced cushioning systems built into the running mat. This minimizes joint impact, making treadmill walking safer for people with ankle, knee, or hip vulnerabilities.
- Incline Option: The incline function on an electronic treadmill significantly increases the intensity of the workout. It emphasizes your glutes, hamstrings, and calves while making your heart and lungs work harder. The result will be a more toned lower body and a more efficient cardiovascular system.
- Cardiovascular Benefits: Walking on a treadmill has been shown to help strengthen your heart and improve cardiovascular efficiency. It helps to remove triglycerides and cholesterol that may clog up the arteries and reduce blood pressure.
How Many Calories Will the 12-3-30 Workout Burn?
The exact number of calories you’ll burn on this, and any other, program depends on such variables as your age, weight, and the amount of muscle you have. You can expect to burn between 400 and 800 calories in a 30-minute uphill climb such as this. Check out our convenient Calories Burned on a Treadmill calculator.
Research shows that walking on an incline significantly increases calorie burn. A 2012 study revealed that setting the treadmill incline to 5% increased the calorie burn by 17%, and setting it to 10% whacked it up by 32%. 
From these study results, we can extrapolate that increasing the treadmill incline by 1% increases the calorie burn by about 10 calories for every mile traveled. At a speed of 3 miles per hour, you will burn an extra 15 calories for every incline percentage during the 30-minute workout.
When we multiply that extra 15 calories per percentage of incline by twelve, we end up with 180 calories.
A 155-pound person will burn 232 calories walking on a zero incline at a speed of 3 miles per hour for 30 minutes. Putting the treadmill at a 12% incline will add another 180 calories for a total energy expenditure of 412 calories.
Can You Really Lose Weight on the 12-3-30 Workout?
Yes, you can lose weight on the 12-3-30 workout, which many people have proved. The key to weight loss is the ability to maintain a negative calorie balance, where your body is burning off more energy than it is taking in.
As we’ve just seen, this workout will help you burn a significant number of calories. That will help you achieve a negative calorie balance. However, you must pair it with a reduced food intake to be effective.
After all, your 400-calorie energy burn from the 12-3-30 workout will be wiped out with a single serving of macaroni and cheese.
To successfully and consistently achieve the required negative calorie balance, you must eat fewer calories than your body needs. This, combined with the extra calorie deficit from exercise, forces your body to turn to its stored energy reserves (i.e., body fat) to meet its energy needs.
To eat fewer calories than your body needs, you must first know what that figure is. This is called your Total Daily Energy Expenditure (TDEE). To find out what yours is, you can use our online calculator.
Reduce your daily calorie goal by 250-500 calories to create a negative calorie balance. You’ll then have to count calories to monitor your caloric intake. You can do that painlessly with various mobile apps and online tools designed for tracking food and calorie consumption.
Some popular options include MyFitnessPal, Lose It!, and Cronometer. These tools help you stay within your calorie limit and make informed choices about the foods you consume to support your weight loss goals.
How Many Times Per Week Should 12-3-30 Be Done?
Lauren Giraldo achieved her 30-pound weight loss by doing the 12-2-30 workout five times per week. By doing so, she met the aerobic exercise guidelines of 150 minutes per week set by the Centers for Disease Control (CDC).
For some people, though, five sessions on the treadmill at a 12% incline will be too much. At the start, you’ll probably experience quite a bit of delayed onset muscle soreness (DOMS), especially in your glutes, hamstrings, and calves.
I recommend giving yourself a day’s rest and recovery between sessions until your body has adjusted to this new form of stress. Two to three sessions per week is a good starting goal.
Rather than doing five sessions of 12-3-30 per week, you might find it more motivating to change things up with different types of cardio to get in your 150 minutes per week.
A couple of excellent options are rowing and using a SkiErg, which is similar to rowing, except that you’re doing it in a standing position, pulling with your arms rather than pushing with your legs.
These two exercises activate your upper body muscles while working your cardiovascular system and burning calories. That makes them an excellent counter to 12-3-30, which is mainly lower body-centric.
What are the Drawbacks of 12-3-30?
The 12-3-30 workout is not for everyone. Walking for half an hour at a 12% incline is a challenging proposition for anyone. It places more stress on the joints than walking on a flat surface.
People with lower back issues or ankle, knee, or hip problems may find the extra stress on those parts of the body too much. They may choose to start with a less aggressive incline, like 5%, or stick with a zero incline and walk for 45 minutes.
Some people may also experience balance issues when walking on such a steep incline. Those with a history of shin splints should also be cautious about the 12-3-30 workout, as walking on an aggressive incline will directly challenge the shins. Wear the right shoes for your gait and do warm-up stretches before starting.
The 12-3-30 was the only workout that Lauren followed. While it helped her achieve her weight loss goal, it didn’t significantly improve her strength and muscle tone, especially in the upper body.
Exclusively focusing on one form of exercise is not a good idea. A well-rounded fitness program will include strength, balance, functional and muscle-building training, and cardio.
Limiting your 12-3-30 workout to two or three sessions per week and adding a couple of resistance training sessions that include an element of balance and functional work will cover all of your fitness bases.
Modifying the 12-3-30 Workout
The 12-3-30 workout provides a template for an effective cardio workout. However, it can be modified to suit your circumstances and available equipment.
If you are a relative newcomer to exercise or aren’t used to working out on a treadmill, you might want to start with a lower incline and gradually build up to 12%. I recommend beginning with a 5% incline and then adding 1% per week.
You can always hit the great outdoors if you don’t have access to a treadmill. Find an area with plenty of hills and varying inclines to simulate the treadmill’s incline.
You can also do a similar workout on other gym equipment, such as an elliptical, cycle, or stepper. Most commercial ellipticals will allow you to adjust the incline, but you’ll have to increase the resistance on the stepper or cycle to make up for the treadmill incline.
How to Safely and Effectively Do the 12-3-30 Workout
Exercising on a treadmill is not as easy as it looks. Over the years, I’ve seen many nasty accidents that could have easily been prevented by following some simple safety guidelines. The following tips will help keep you safe when doing the 12-3-30 workout.
Getting Set Up
- Ensure your shoelaces are tied properly.
- Begin by straddling the treadmill with your feet on the sides of the running belt — never place your feet on the running belt before it starts moving.
- Attach the treadmill’s safety clip to your collar or belt, and press the start button. As the belt starts moving, step onto it and begin walking while holding the side or front handlebars.
- Gradually release your grip, maintaining an even toe-to-heel stride.
- Look straight ahead.
- Perform a proper warm-up with a few minutes at a slow, steady pace before transitioning to your workout speed.
- Keep your feet and body at the front of the treadmill to retain proper running form.
- Avoid holding down the speed button, as it can lead to a rapid and potentially dangerous speed increase.
Choosing the Right Footwear
Never run on a treadmill barefoot or in socks only. The smooth surface of the running belt increases the risk of slipping, especially if sweat is involved.
For casual runners that don’t go over 8 miles per hour, everyday running shoes are generally sufficient.
Dedicated runners or those transitioning between outdoor and treadmill running can use the same pair of shoes. If buying shoes specifically for treadmill workouts, prioritize extra cushioning in the heel and flexibility. However, ensure the shoe does not bend in the arch.
Key Tips for Proper Treadmill Form
Use the following form cues to improve your training experience:
- Avoid holding onto side rails or handlebars, and maintain a natural, upright posture.
- Walk toward the front of the running belt to prevent leaning backward.
- Keep your torso upright, and avoid looking down or leaning forward.
- Allow arms to move naturally, pumping alongside the body during power walking.
- Avoid exaggerated arm movements that may disrupt balance.
- The impact should be on the heel, naturally rolling through the foot to push off from the toe.
- Avoid increasing stride length as the treadmill running pace quickens.
- Maintain a centered position on the running belt; move in a straight path; correct any instances of drifting.
- It is important to avoid stopping while the treadmill belt is moving.
- Maintaining focus is essential to reduce the risk of injury or alteration to your running motion.
- You should adjust the treadmill’s incline to a level that doesn’t force you to lean backward. This will help you avoid hunching over, which can lead to soreness in your lower back. Reduce the incline to a more appropriate level if you find that 12% causes discomfort.
- Ensure that your shoes are securely fastened, and wear fitted clothing to prevent tangling without impeding blood flow.
The 12-3-30 workout is demanding but efficient. This exercise routine, combined with a diet with fewer calories, will assist you in reaching your weight loss goals.
The challenge of keeping a 12% incline for thirty minutes will put this workout beyond the capability of most beginners. Modify it to meet your current abilities and progressively work up to the 12% incline.
You should also include other forms of exercise, such as strength training, to cover all your fitness bases.
Have you been doing the 12-3-30 workout? Tell us about it in the comment section below.
- Silder A, Besier T, Delp SL. Predicting the metabolic cost of incline walking from muscle activity and walking mechanics. J Biomech. 2012 Jun 26;45(10):1842-9. doi: 10.1016/j.jbiomech.2012.03.032. Epub 2012 May 11. PMID: 22578744; PMCID: PMC4504736.