In 2019 Lauren Giraldo introduced the 12-3-30 treadmill workout, and the trend has continued to gain attention — especially after she posted a video touting its perks in 2020. Since then, the hashtag #12330 has garnered a whopping 98.9 million views on TikTok. But is the 12-3-30 workout really worth the hype, and is it effective? Here’s what you need to know — and how to tweak the approach depending on your fitness level.
What Is the 12-3-30 Workout?
Simply apply these settings to the treadmill:
Incline 12 percentSpeed 3 miles per hourTime 30 minutes
And that’s it! Giraldo credits her 30-pound weight loss to the 12-3-30 workout. After two years, she’s been able to keep the weight off by doing the 12-3-30 workout about five times a week, she says. Her 2020 video inspired people to participate in the #12330challenge (37.6 million views), which challenges gym-goers to do this workout five times in one week. It also challenges multiple areas of the body. “Walking on an incline targets the muscles in your posterior chain (glutes, hamstrings, low back, and calf muscles) more so than walking on a flat surface,” Hart says. And don’t be fooled by the fact that this is a walking workout; for most people, it’s going to be pretty intense, says Jordan D. Metzl, MD, a sports medicine physician at the Hospital for Special Surgery in New York City. “Even though the pace is a fast walk, the uphill grade of 12 makes this a moderate- to high-intensity workout.” The 12-3-30 workout is also safe for people of all fitness levels to try, so long as they don’t experience pain or have medical restrictions on exercise, Hart says. But, as Dr. Metzl suggests, beginners may find the incline and speed challenging to keep up for the full 30 minutes. If this happens, Hart suggests starting with a lesser incline (try 8 percent), speed (try 2.5 miles per hour), or time (such as 20 minutes). As you get more comfortable, work up to the 12-3-30 formula, she says. “There’s no ‘magical’ reasoning behind the exact numbers of 12-3-30.” Metzl adds that what will make this workout most worthwhile is doing it regularly. “The best kind of workout is the one that people will do consistently,” he says. “The holy grail of any workout is actually doing it day after day, month after month, and year after year.” The U.S. Department of Health and Human Services recommends American adults each week do 150 to 300 minutes of moderate-intensity cardio, or 75 to 150 minutes of vigorous intensity activity. So, depending on your fitness level (and whether this workout is moderate or high intensity for you), doing the 12-3-30 treadmill routine about 3 to 5 times per week meets those benchmarks, Metzl says.
Who Should Try (and Who Should Avoid) the 12-3-30 Workout
The 12-3-30 workout provides the type of cardiovascular exercise we all need for general health, Hart and Metzl agree. And because it’s low-impact (if you have joint issues and need to pay attention to that) and customizable for all fitness levels, it’s going to be a good workout for most people, Metzl says. But do tailor it to your skill level if the 12-3-30 formula is too difficult to start with. Going out too quickly or for too long can be a recipe for injury. Don’t do the workout however, if you feel joint discomfort while walking on the incline, Hart says. And if you have any health problems or injuries that might limit your ability to safely exercise, be sure to check with your doctor first about whether the workout is right for you and how to tailor it to your fitness goals.
Summary
The 12-3-30 workout is a safe, time-efficient, and effective low-impact cardio workout that’s suitable for people of most ages and fitness levels. If it’s too challenging when you begin, dial down the intensity by lessening the speed, incline, or time. No treadmill? Don’t sweat it! Hart and Metzl say that any hill will do as a supplement to the cardio machine. “Find a larger hill in your neighborhood, and try to walk up it at a continuous, steady pace. Once you reach the top, head back down, and continue the hill repeats for the desired time,” says Hart.
