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What is 12-3-30? People are losing weight with this walking treadmill workout

The 12-3-30 workout is a viral walking treadmill routine. Experts weigh in on how to try it safely to lose weight and improve endurance.

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Walking treadmill workouts are an easy way to jumpstart a new fitness routine or add variety to an established one. One of the most popular routines is the 12-3-30 treadmill workout, which continues to be a fan favorite since it went viral in 2020.

The workout is simple: Set the treadmill to an incline of 12 (or lower — choose a challenging incline for your fitness level!) at a speed of 3 miles per hour and walk for 30 minutes.

The routine doesn’t require a lot of time, but if done consistently it can improve endurance and aid in weight loss. One of the reasons why it is so popular is that it can deliver these results with absolutely no running required!

Walking is lower-impact and less likely to cause injury than running, and has many important benefits, such as lowering blood pressure and cholesterol, boosting metabolism, improving mental health by reducing anxiety and depression, and even lowering the risk of some cancers.

The 12-3-30 trend took off when health and beauty influencer Lauren Giraldo posted about it on YouTube in 2019 and then again on Tiktok in 2020, sharing that the workout helped her lose 30 pounds and keep it off.

“I used to be so intimidated by the gym. It wasn’t motivating, but now I go do this one thing and I can feel good about myself,” she said on TikTok. “I look forward to it. It’s my me-time.”

Giraldo’s emphasis on self-care and attainable fitness goals has resonated with a wide audience. Her initial post has over 2.8 million likes.

The influencer, who is not a fitness expert, chose the numbers 12, 3 and 30 because the highest incline on the treadmill at her gym was 12, she didn't enjoy running and three miles per hour felt like a good, brisk walking pace to her, and her grandmother always advised to exercise at least 30 minutes each day.

Clearly, the incline and intensity in the workout are personal to her, so people should consider their own fitness level and goals when trying it, and make adjustments as needed.

Physical therapist Vijay A. Daryanani, a certified personal trainer at Spaulding Outpatient Center, a hospital that partners with Harvard Medical School, says the simplicity of walking for 30 minutes is an attainable goal that’s appropriate for most people.

“I think the 3 mph for speed is good for most people, but the incline is a critical piece," Daryanani tells

He recommends that people pay close attention to their posture while walking on an incline.

“When I’m training someone, I will adjust the incline safely and with guidance to maintain posture, balance and stride. Inclining a treadmill is similar to walking up hills, which places different stresses on the musculoskeletal system,” he says.

Here’s what to know about preventing injury and walking for weight loss if you’re ready to try the 12-3-30 workout yourself.

The 12-3-30 workout was first popularized by health and beauty social media influencer Lauren Giraldo, who says the treadmill workout helped her lose 30 pounds.
The 12-3-30 workout was first popularized by health and beauty social media influencer Lauren Giraldo, who says the treadmill workout helped her lose 30 pounds.laurengiraldo/ Instagram

What is the “12-3-30” workout?

Giraldo’s workout is guided by three settings on the treadmill:

  • Incline: 12
  • Speed: 3 mph
  • Time: 30 minutes

According to Giraldo's TikTok video, she does the workout approximately five times per week and it helped her drop 30 pounds. “I obviously noticed the changes in my body, but I was most happy with the changes that I felt mentally,” she said. “I was proud of myself every day for getting on the treadmill and having my ‘me time’ for 30 minutes. I feel accomplished every time I do it.”

For Giraldo it served another important purpose: getting her comfortable stepping foot in the gym. “The thing about 12-3-30 is it made the gym so much less of a scary place. I feel confident in the gym now, and I sometimes incorporate weights and other exercises into my workout,” she said.

Benefits of the "12-3-30" workout

As previously reported by, walking comes with a myriad of health benefits including: Improving cardiovascular health and blood pressure, controlling blood sugar and reduce your risk of diabetes, increasing your metabolism, aiding in weight loss and maintenance and increasing your aerobic capacity.

The U.S. Department of Health and Human Services recommends moderate-intensity aerobic exercise for 150 to 300 minutes a week. Doing the 12-3-30 workout five times a week will get you into the low end of that range.

Walking is also a low-impact alternative to running, which is good for people with joint issues, but adding the incline to your walks increases the intensity and makes it a more challenging workout. It also has toning benefits for the lower body. "Walking on an incline will engage your leg muscles more than walking on level ground," TODAY fitness contributor Stephanie Mansour previously wrote on "This will make for a more intense workout for your glutes, hamstrings and quads, while also increasing your heart rate."

Is the "12-3-30" workout safe?

At first, Giraldo couldn’t make it the full 30 minutes. “I definitely had to work up to the 30 minutes. I couldn’t get through it without losing my breath and started out by taking a break after the 10 or 15-minute mark,” she said.

Although 12-3-30 is a relatively straightforward treadmill workout, it isn't something you should just jump right into, Dr. Dennis Cardone, osteopathic sports medicine specialist and chief of primary care sports medicine at NYU Langone Health, told TODAY.

“If someone is working that hard with this workout and they are a 20-something, young and healthy, and they are struggling, you see it was a pretty significant workout," Cardone says. "It’s just too much too soon and it should really have a recovery day as well."

That’s not to say that there can’t be benefits to adding an incline to your workout. “It certainly adds more stress to a workout in the sense that people are getting more of a workout in a shorter period of time; the muscles are working harder,” says Cardone.

But, he adds, the risks may outweigh the benefit when it comes to adding a significant incline to your workout.

“The problem is people don’t think that walking is a stressor. They think ‘what’s the big deal using an incline? I’m only walking.’ But it really is a big stressor: low back, hamstring, Achilles tendon, knee, plantar fascia … these are the areas where we see some significant injury related to inclining a treadmill,” he said. “As a general observation, anytime anybody begins or changes a workout or adds something like an incline, they have to follow the rule to do it slowly, otherwise they are certainly at significant risk for an overuse injury.”

Can you lose weight with the "12-3-30" workout?

Giraldo said that she lost 30 pounds with the 12-3-30 workout and has kept it off for years.

Gradual, steady weight loss of about 1 to 2 pounds per week is optimal for keeping the weight off, according to the Centers for Disease Control and Prevention. "Generally to lose 1 to 2 pounds a week, you need to burn 500 to 1,000 calories more than you consume each day, through a lower calorie diet and regular physical activity," the Mayo Clinic explains.

Walking for 30 minutes burns about 125 calories for a 150-pound person — and adding an incline will increase that calorie burn. So with healthy diet changes, the 12-3-30 workout has the potential to burn the calories needed for steady, gradual weight loss.

Want to give it a try? Follow these guidelines for a safe and effective workout

“(Giraldo) did well, but most people never make it there because they will get an overuse injury and will be taken out of the game. It’s a great goal, but it’s just not realistic for most of the population," said Cardone. "If you just do one activity — we don’t have to bash just this one — but whatever activity, if you keep doing it day in and day out, it's just a setup for injury.”

So instead of jacking that incline way up, here is the safe way to try Giraldo's workout:

  • Don’t be fooled by the treadmill: “People think the treadmill is so safe; it’s not outdoors, it’s a soft, forgiving surface. But it’s not that different from walking up a hill; you’re not protecting yourself that much more by being on a treadmill as opposed to being out on a road,” warned Cardone. “Thirty minutes walking up a mountain, it’s pretty tough when you think about it. People feel a little overconfident about the treadmill.”
  • Adjust the numbers to meet you where you’re at. “Don’t incline so rapidly, maybe don’t even start at 30 minutes; 3 mph is reasonable, but maybe slow down your duration of workout and incline to work up to that," suggested Cardone. "Start flat on a treadmill, and do 0-3-30. Once that is comfortable for you, then start inclining, don’t go to 12 right away. Over 3 weeks start slowly progressing your incline, maybe 10-20 percent per week.”
  • If you're new to fitness, start on flat ground. “If someone is outdoors and starting their workout program, whether it’s walking, jogging, interval training, don’t look for a hill," said Cardone. "First, tolerate flat. Once you’re doing that, then if you want to add some hills into your workout, fine. But don’t go looking for hills at the start of a program.”
  • Gradually increase incline: “Slowly progress your incline, start at the lowest setting and it’s a gradual increase, like any other workout in terms of increasing mileage or intensity,” said Cardone. “This workout starts at a 12-degree incline, so I’d say go at 4-degree intervals. So gradually increase it over a 3-week period to get to that 12 degrees.”
  • Don’t do it every day. “Almost whatever the routine is, the general rule is there should be a recovery day or at least alternating with some other activity in order to try to avoid overuse injuries," said Cardone. "I wouldn’t discourage people from doing some sort of activity most days of the week, just not the same activity. Have a recovery day where you are doing some sort of alternate activity, maybe that might be the elliptical trainer, a bicycle or in the swimming pool, whatever you have available."
  • Supplement with strength and stretching. The bent posture of walking uphill places stress on your low back, Achilles tendon, calf muscles, plantar fascia and hamstring muscles, said Cardone. “Those are stubborn problems and people don’t want those kind of injuries, once they kick in, they are tough to treat," he said. He suggested doing core-strengthening exercises as well as stretching those areas specifically to help reduce your risk of injury while walking or running.
  • Consider something lower impact. If you are just getting into fitness, Cardone advised starting with lower-impact workouts. “Bicycling, elliptical trainer, swimming, cross-training type activities, are even safer. Those are great activities to start a workout routine and build up your cardiovascular endurance; you’re not doing a lot of impact, it’s a little more forgiving on the joints and also on muscle tendons," he said. "So maybe do the treadmill 2 or 3 days a week and the other days these other activities; that is going to keep people out of trouble.”

How many times a week should I do the "12-3-30" workout?

Even if you’re following these guidelines, the workout should still be done at most, every other day, alternating with other lower-impact activities.

In order to get the benefits you seek from any exercise — whether that be weight loss, toning or overall health — the key is to find a program you can stick with, said Cardone. That means the fitness routine you choose not only needs to be safe, so you’re not sidelined by an injury, but “it has to be something they enjoy, and if they are only doing one activity they are going to burn out, not just physically, but mentally,” he said.

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