What Is the ’12-3-30′ Workout—and Is It Effective and Safe?

If you’re active on social media, you may have seen someone raving about the “12-3-30” workout. This cardio routine requires just 30 minutes and a treadmill—and no running. Its simple formula touts many potential benefits, like building strength, increasing stamina and aiding weight loss.

Almost sounds too good to be true, right? To get the scoop on its effectiveness, we consulted Julie Floyd Jones, a certified personal trainer and wellness specialist.

What Is the 12-3-30 Workout?

The 12-3-30 workout was coined by 24-year-old social media maven and YouTuber Lauren Giraldo. It consists of setting a treadmill to an incline of 12 and walking at 3 miles per hour for 30 minutes. Sounds easy enough. Well, according to hundreds of commenters, it’s actually “a lot harder than it seems.”

Giraldo first shared the treadmill routine in a 2019 YouTube video, but it wasn’t until she posted it to Instagram and TikTok in 2020 that it gained traction. In a 37-second TikTok video, she claims this routine helped her lose 30 pounds and overcome gym intimidation.

Potential Benefits of the 12-3-30 Workout

Walking has many benefits of its own—like keeping blood sugar in check, strengthening the heart, boosting mood, contributing to weight loss and even helping to reduce the risk of dementia. It’s also more gentle on the joints than other cardio exercises, like running.

“[The 12-3-30 workout] is an easy formula to remember,” says Floyd-Jones. “It only takes 30 minutes, and while it is challenging because of the incline and duration, it is simply walking—which is attractive to those who don’t enjoy running or who are unable to run.”

Adding the 12% incline intensifies this treadmill routine and drives up heart rate, mimicking an uphill hike. “When we have to climb a hill it intensifies the workout—increasing heart rate, respiratory rate and potentially caloric expenditure,” says Floyd-Jones. “You are definitely going to improve cardiovascular health and cardiovascular endurance and strength. Due to the incline, you should also improve strength in your lower body.”

Working against gravity on an incline gets you winded faster than, say, a walk in a park. So, the short answer: Yes. This workout does have its benefits, but it shouldn’t be your sole source of physical activity.

How Do You Do the 12-3-30 Workout?

First things first—fuel up. According to the American College of Sports Medicine (ACSM), exercising on an empty stomach may cause nausea, so having something to eat one to three hours prior to your workout can help prevent that queasy feeling and give you the fuel and energy you need to get through your workout.

What to eat? Some of this is trial and error since everyone’s body is different, but generally, opting for a meal or snack that wields a combo of carbohydrates and a small amount of protein is best. If you need something last-minute prior to your activity, a piece of fruit with a few nuts or a little nut butter can do the trick.

The Best Fitness Foods: What to Eat Before, During and After a Workout

As with any other workout, resist the urge to jump in too quickly, and take time to warm up and ease into the workout. Floyd-Jones recommends beginning with pre-workout stretches to activate your glutes, calves, hamstrings and hips. Once on the treadmill, ease into the incline. “When I do any type of treadmill work with my clients, I always have them do the first couple of minutes flat—at 0% grade—to acclimate to the treadmill and begin to warm up,” says Floyd-Jones. “Then, I start to adjust the incline, and potentially the speed.”

It’s OK to push yourself, but make sure you’re also listening to your body—duration and pace can always be adjusted.

You’re not off the hook once the 30 minutes are up. Allotting time to recover after a good sweat optimizes benefits and lowers risk of potential injuries. “Any time you’re going up an incline for that prolonged period of time, you need to take time to undo it,” says Floyd-Jones. “Your muscles are working, tightening and strengthening, so then you need to go back and make sure you’re lengthening them again.”

Floyd-Jones suggests doing basic foam-rolling exercises and calf and hamstring stretches to help your body cool down and prevent injury.

No Treadmill? Don’t Sweat It

The 12-3-30 is difficult to replicate on other machines due to the lack of incline. But upping resistance and stride on ellipticals and Arc Trainers is a good lower-impact alternative way to intensify your workout—and may even be a better option for some.

“I would tell my clients to be cautious doing prolonged incline if they are dealing with plantar fasciitis, tight calves or hamstrings or low back pain,” advises Floyd-Jones.

Or, if you don’t have access to a gym or machines, simply hitting the hills outside is also a great way to get your heart pumping.

Can You Do the 12-3-30 Workout Every Day?

The Physical Activity Guidelines for Americans recommends adults get at least 150 minutes of moderate-intensity physical activity per week or at least 75 minutes of more vigorous activity per week. So knocking out this 30-minute uphill workout several times a week hits that requirement.

But while the 12-3-30 workout does have its benefits, adding other elements of physical activity is necessary for a more well-rounded routine—and body. Many fitness fans are going all-in on 12-3-30, with some doing it every day.

Floyd-Jones warns against this and recommends sticking to the 12-3-30 workout two or three days a week max. Alternative days are better spent building up other muscles—like those of your core and back—by doing resistance and mobility-based training or body-weight exercises at home.

The Bottom Line

The 12-3-30 treadmill workout is an effective aerobic routine that gets your heart rate up, builds strength and endurance and may even contribute to weight loss when paired with a balanced diet. It’s memorable and requires one piece of equipment only, making it feel achievable for many.

With that said, this workout is no magic solution. For best results, stick to 12-3-30 a couple of days a week and use the remaining days to engage other muscles through strength and mobility training, a fitness class you enjoy or a walk around the block. You know your body best, so stay in tune with yourself and go at your own pace.