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What is '12-3-30'? The walking treadmill workout can help you lose weight

The 12-3-30 workout is a viral walking treadmill routine. A sports medicine doctor weighs in on how to try it safely for weight loss.

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You may assume that you need to run or spend hours on the treadmill to see results. But a popular exercise routine is proving that walking treadmill workouts can be an effective way to build your endurance and shed some pounds without requiring a ton of time.

What’s known as the 12-3-30 workout, which only requires a treadmill and your legs, can offer the benefits of weight loss, endurance and strength-building, and it’s approachable for people with a range of fitness levels.

The best part? The intense workout requires absolutely no running. All you have to do is set your treadmill to an incline of 12 (or a number that feels steep to you), set your speed to 3 miles per hour and walk for 30 minutes.

Research shows walking can boost your health in numerous ways, such as reducing anxiety and depression, combatting some aspects of aging (like the risk of dementia), and of course, helping your heart and other internal organs function better.

It’s all of these benefits and more that propelled the 12-3-30 workout to viral status in 2020 and make it one of the most popular workouts on social media to this day — especially TikTok, where the hashtag #12330workout has 339 million views.

The 12-3-30 workout was first popularized by health and beauty social media influencer Lauren Giraldo, who posted about it on YouTube in 2019. A subsequent post on TikTok in November 2020, which made the trend explode, has garnered 2.8 million likes. In the clip, Giraldo explains how the treadmill workout helped her lose and keep off about 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.
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

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

Giraldo also revealed to TODAY.com how she came up with the numbers she’s come to rely on. “I’m not a runner, and running on the treadmill was not working for me,” Giraldo said via email. She added that the treadmill at her gym had 12 as its highest incline, 3 miles per hour felt “right” because it was just walking, and her grandma always recommended 30 minutes of exercise daily.

Twelve is a steep incline, so unsurprisingly, it took Giraldo a couple of months to start enjoying, and even look forward, to her workout. One thing that kept her going was the fact that 30 minutes just felt so doable: “I found that just focusing on myself for 30 minutes a day was not only great for my body, but also great for my mentality,” she said.

A few months after her TikTok went viral, Giraldo shared another video about how the workout has been helping other people, too — not only with weight loss, but with strengthening and creating muscle definition in the core and legs. In the comments, many users shared that it’s the steep incline that makes the difference and helps them feel like they’re getting a good workout.

If you’re interested in trying the 12-3-30 workout yourself, here’s what to know about whether it’s safe and how to integrate it into your own routine.

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.

What is the "12-3-30" workout good for?

So what are the benefits of the 12-3-30 workout?

As previously reported by TODAY.com, 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 TODAY.com. "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.

Dr. Dennis Cardone, osteopathic sports medicine specialist and chief of primary care sports medicine at NYU Langone Health, told TODAY that this isn’t a workout you should jump right into.

“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. It’s just too much too soon and it should really have a recovery day as well,” says Cardone.

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,” said 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. According to the Centers for Disease Control and Prevention, gradual, steady weight loss of about 1 to 2 pounds per week is optimal for keeping the weight off. "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," according to the Mayo Clinic.

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 set up 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 and once you’re doing that then you 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. Which means it 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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