Overthinking the numbers of your treadmill workout is a treasured pastime of anyone who’s ever tried to suffer through a sweat session. But maybe those numbers don’t have to be as complicated as you think. When it comes to incline, speed, and duration, the three most important numbers you need to remember are 12-3-30.
It sounds almost too simple: You set your treadmill at 12 percent incline, at 3 mph, and walk for 30 minutes. A half-hour walk shouldn’t be too strenuous, right?
But there’s a reason this workout exploded on social media during COVID lockdowns and many trainers continue to encourage it today—it works! And it might be more challenging than you expect.
Is it that hard?
The Cleveland Clinic explains the challenge factor by noting that walking uphill is harder on your body than walking on a flat surface, which can double the calorie burn depending on your weight and fitness level. According to a peer-reviewed study by the High Altitude Exercise Physiology Program at Western Colorado University, participants burned 220 calories per session on average. Possibly more importantly, participants rated the workout as highly enjoyable, which means someone is more likely to stick with it.
Want to give it a try? Get the most out of it (and keep it safe):
Start (and go) at the intensity that’s right for you… As with all workouts, it’s not a one-size-fits-all thing. “A fixed 12 percent and 3 mph [walk] can be too hard for beginners or too easy for the very fit,” says Dani Singer, founder of a regional personal training studio. He recommends adjusting the speed and incline as needed.
Make sure you’re using good form… Watch your posture, swing your arms to keep your momentum going, and don’t lean on the handrails of the treadmill. Bad form can lessen the effectiveness of the workout at best and put you at risk of injury at worst. “Rail-grabbing nerfs the workout,” Singer says. “Holding the handrails measurably reduces [oxygen consumption] and heart-rate responses, so you get less conditioning at the same settings.”
Make it part of a varied routine… Doing this workout five days a week is enough to get the 150 minutes of moderate cardio recommended each week, but don’t neglect strength training or flexibility training. “Doing the same treadmill routine daily can sometimes lead to overuse injuries,” says Dr. Suzanne Manzi, board-certified physician in obesity medicine. “It’s a good idea to mix in other forms of aerobic exercise, strength training, or cross-training as well.”
