The 12-3-30 workout, explained

When a single workout video gets more than 1.5 million views on YouTube, you pay attention. That’s exactly what’s happened with the 12-3-30 workout, an inclined treadmill workout that went viral on social media. But unlike some health-focused videos that are mostly just fluff, experts say this one actually has some solid science behind it. Learn what the workout is, how to do it, and the 12-3-30 results you might enjoy.

Key takeaways

• The 12-3-30 workout is an inclined treadmill workout that rose to popularity on social media. It involves walking on a 12% incline at 3 mph for 30 minutes.

• Incline walking has many benefits, including greater calorie burn than walking on a flat surface, increases in cardiorespiratory fitness, and improvements in leg strength. 

• 12-3-30 can be done regularly, but it should not be the only workout you do all week. It counts as an aerobic workout, and experts recommend including strength training as well.

The 12-3-30 workout is a walking treadmill workout popularized by content creator Lauren Giraldo in a video she posted in 2019. The name of this workout represents the specific treadmill settings used, but essentially you just walk on an incline at a steady pace.

This workout is a simple concept, which is why the creator thinks 12-3-30 really took off and resonated with her followers. All you need is access to a treadmill and the ability to change the settings. 

The settings

• Set the treadmill incline to 12%.

• Set the speed to 3 mph.

• Walk for 30 minutes.

  
  

How to modify it for beginners

This workout may sound simple, but that doesn’t mean it’s easy. Even in her video, Geraldo talks about how she got breathless pretty quickly when she first started doing this workout, but that over time her fitness improved.

So, if you are new to incline walking or hill workouts, you may need to adapt 12-3-30 in the beginning. “That speed — 3 mph — is pretty fast for most people at that incline,” says Tom Holland, M.S., CSCS, an exercise physiologist and adjunct professor in biomechanics and strength and conditioning at the University of Bridgeport in Connecticut. That’s why you may want to slowly build up to the full 12-3-30. Holland recommends first walking flat at 3mph for a certain period of time. The specifics are up to you, but you could start with 10 minutes, gradually adding time from there. After you get to 30 minutes, add a small incline, then slowly increase it from workout to workout until you reach a 12% grade. 

If you start this workout off too intense for your fitness level, there’s a chance you’ll need to grasp onto the treadmill handlebars to keep yourself on the equipment. That will stall your progress. “Once you grab onto the bars, you are decreasing your expenditure and increasing the chance of injury,” says Holland.

Incline walking is more difficult than doing it on a flat surface because you’re fighting against gravity. Your body has to exert more energy to go the same speed. That puts demand on your lower body muscles, notably your glutes, hamstrings, and calves, says Colin G. Pennington, Ph.D., an assistant professor of exercise science at Gwynedd Mercy University in Pennsylvania. Your body must recruit more muscle fibers to meet this demand.  

You’ll also notice that you breathe heavier and your heart beats faster on an incline. “Just as your lower body muscles will work harder at incline, so will the cardiac muscle [a.k.a. your heart],” says Pennington.

“The structure is popular for good reason: It’s straightforward, doesn’t require complex equipment, and is metabolically effective,” says Pennington. Here’s a deeper look into the potential 12-3-30 benefits you might expect:

Goes easy on your joints 

One of the perks of incline or hill workouts is that there is less “ground reaction force,” or the impact on your body when you make contact with the ground. This results in less strain on your hips, knees, and ankles, says Pennington. The 12-3-30 workout is also not very overwhelming to remember: You just need one piece of equipment (a treadmill) and the settings are easy to program. 

Builds cardio endurance

Incline walking is harder than walking on flat ground, which can send your heart rate higher. The more this happens, the more you’ll improve your cardiorespiratory fitness and endurance.

Burns calories and supports fat loss

During exercise, your body burns calories to give your muscles energy. A small study on the 12-3-30 workout, published in the International Journal of Exercise Science, found that this workout burns a higher percentage of calories from fat compared to a self-paced run. That said, the most important point for weight loss is increasing the total number of calories burned, not focusing too much on where they come from, the researchers point out. Ultimately, they found that a self-paced run and 12-3-30 each burned about 300 calories — but people completed the run workout faster (in 24 minutes). 

Works for beginners 

Although 12-3-30 might be difficult, the structure of the exercise is beginner-friendly. You can — and should! — modify the incline, speed, or duration as needed to challenge your current fitness level. What’s more, you do not need classes or fancy equipment — just a treadmill.

In general, walking is a great workout. And it’s something most people can do! And because it’s more strenuous than walking on a flat surface, Holland notes that incline workouts can be great for supporting weight loss. The higher the incline you use, the greater your calorie burn, per a small study in Sports Medicine and Health Science. And remember: You aren’t limited to a treadmill. You can walk or jog on an incline outside on a nearby hill.

You can do 12-3-30 as often as you want, but it shouldn’t be the only type of exercise you do. Make sure to include strength training in your weekly routine as well. If you’re feeling up for it, you can even do both on the same day. “12-3-30 can be done as stand-alone exercise, but it — or a modified format — may be an ideal warm-up or cool-down on strength training days,” says Pennington.

A workout should be challenging, but if you want to stick with it for the long run, it also should feel good, doable, and fun. If you are a beginner to incline walking or starting a new physical activity routine, you can modify this workout in the following ways, advises Pennington:

• Start at a lower grade (incline), such as 3 to 5%; increase the grade each week.

• Start with 10-15 minutes of walking, gradually building to 30 minutes.

• Incorporate intervals, which include a recovery period. Alternate between 3 minutes at a 12% incline and 2 minutes walking flat at a 0% incline.

12-3-30 is an appealing workout because it gives you a goal when you go to the gym (a place that can be a source of intimidation and anxiety, especially if you’re not confident about what to do when you get there). In fact, that “I don’t know what to do” stress is one of the reasons Giraldo said she started doing 12-3-30 in the first place. 

The workout can be useful, alongside other healthy habits, if you’re trying to lose weight and keep it off. One meta-analysis on nearly 7,000 adults with overweight or obesity found that at least 150 minutes of aerobic exercise per week was associated with reduced body fat and waist circumference. The 30 minutes spent on this workout absolutely contribute to that number. The workout can also be logged in the WW app and can also count towards your activity goals when you’re following a Weight Watchers plan, like Core+ or the GLP-1 Success Program.

The 12-3-30 treadmill workout is an incline workout where you walk on a 12% incline at 3 mph for 30 minutes. This workout burns calories while strengthening your leg muscles and improving your cardiovascular fitness. Another benefit to this approachable workout is that walking on an incline can be easier on your joints than running or walking on a flat ground. “It’s speed training without the impact,” says Holland.