I tried the 12-3-30 workout again - 5 reasons this low-impact exercise is great for beginners

You may remember the 12-3-30 workout from a few years ago. Its simple premise and set-up made it a viral sensation on social media - and a great option for those looking to get fitter, maintain muscle, and improve their balance. In 2026, it's as good as ever.

The 12-3-30 is a treadmill workout made popular by influencer Lauren Giraldo. She said: "I used to be so intimidated by the gym, and it wasn't motivating. But now I go and do this one thing, and I can feel good about myself."

In a similar vein, I swapped my after-work walking workout for this session when the ongoing summer heat took a toll on my motivation. I decided it was too hot outside, so I headed to the gym and revisited the 12-3-30 for all its low-impact cardio benefits.

How to do the 12-3-30 workout

The 12-3-30 workout is very simple. Lace up your running shoes and hop on a treadmill, then follow these steps:

• Adjust your incline to 12.
• Increase speed to 3mph or 4.8kph, depending on your treadmill settings)
• Set a 30-minute timed workout on your machine or fitness tracker

If this feels too hard at the beginning, set the incline to three or four instead of 12 and challenge yourself to hold the pace for as long as possible. Build up your time and gradient as you get fitter and stronger.

The speed at which you progress will be different for everyone, so don’t compare yourself - work at the level that’s right for you. It should feel challenging, but not so much so that you feel out of breath and can't continue.

It's also important to maintain good form as you walk. Engage your core, keep your shoulders back and your head up. Always look straight ahead, rather than down at your feet on the treadmill.

The 12-3-30 workout is a more efficient and effective cardiovascular workout compared to flat-surface walking, says Amanda Place, a certified personal trainer and the founder of Sculptrition. "It also can help with engaging various muscle groups, burning calories, and promoting overall fitness," she says, making it a great workout for beginners.

Benefits of the 12-3-30 workout

1. Builds fitness

When I first started exercising properly, about seven years ago, I found that my cardio fitness was letting me down. It was uncomfortable to work out for any longer than 10 minutes in one go.

I've seen how good the 12-3-30 workout is for building fitness. Today, 10 minutes into the workout, I was in my zone 2 heart rate. This is known as the aerobic zone, and it's about a 6 or 7 out of 10 for intensity. You should be able to have a conversation but not sing. It's ideal for building a baseline of cardiovascular fitness, no matter your fitness level.

A recent study by Queen's University found that this heart rate zone improves cardiovascular fitness by enhancing capillary density (how many blood vessels in a muscle) and stroke volume (the amount of blood pumped out of the heart in every heartbeat) with minimal recovery time or joint stress.

There are ways you can adjust the 12-3-30 workout to make it harder. For instance, adding ankle weights or a weighted vest adds resistance to your legs and glutes, and requires you to focus more on core stability.

2. Low impact

The softer surface of the treadmill and slower pace put less pressure on the joints compared to activities like running. This means less chance of injury and discomfort post-workout and more chance of round two later in the week.

"Unlike high-impact exercises, such as running or jumping, the 12-3-30 workout is low-impact. This makes it suitable for individuals with joint issues or new to exercise," says Amanda.

3. Maintains heart health

It's well-established by health bodies and expert facilities, including the Mayo Clinic and Ohio State University, that aerobic exercise like power walking and running helps keep the heart healthy.

The extra effort compared to regular walking makes it work harder to push blood (containing oxygen) around the body. The heart is a muscle just like any other, the more you use it, the more effective it is. In turn, this lowers blood pressure and reduces the risk of heart disease, type 2 diabetes, stroke, and other serious diseases.

4. Maintains muscle

Trust me, by the time you've done 20 minutes of walking at a 12% incline, you'll be feeling your glutes (buttocks), hamstrings, calves, and lower back working overtime.

Walking uphill forces the muscles at the back of your body, known as the posterior chain, to work harder than they would on the flat ground. This is just enough pressure to preserve the muscle that you have without stressing your joints.

You can further maintain and grow that muscle by combining the 12-3-30 workout with regular full-body strength workouts in the gym.

5. Versatile

While the heatwave rages on, I wouldn't blame anyone for putting exercise last on the list of priorities. However, this workout can be done under the cooling air conditioning in your local gym or in front of the fan, if you have a treadmill at home.

It's also only half an hour. Most people will be able to find this time in their day, either by adding it into an existing routine (like at the end of a dumbbell workout in the gym) or by waking up half an hour earlier. Make the most of the cool mornings.

As many as 8 in 10 women say that time is their biggest limiting factor when it comes to exercise. I certainly fit in this camp. Yet, even in a busy and hot week, I found the time to do the 12-3-30 workout four times. Next week, I'll be aiming for five times.

Can you do the 12-3-30 workout every day?

Yes, if you're looking for a daily exercise, the 12-3-30 workout could be a great choice. The NHS recommends 150 minutes of moderate exercise every week, divided up across seven days. You'd only need to do this workout five times a week to hit this target, leaving plenty of time for rest, recovery, and other workouts.

The experts recommend alternating between the 12-3-30 and strength-focused workouts, like a 30-minute dumbbell workout or an upper-body dumbbell workout, to help maintain and grow the muscles somewhat neglected by cardio. For example, you could do the 12-3-30 three times a week and a type of strength training twice a week to hit the overall quota.