The 12-3-30 workout is a walking incline treadmill routine that people say improves endurance, boost mental health and helps with weight loss.

It makes it feel like you’re walking up a hill. (Incline walking has also been shown to make ankles and knees stronger and more flexible.) You can adjust the incline to 5% or more.

“Walking is also a great active recovery,” she says. Although a walk won’t necessarily ramp up your heart rate the way a run might, it helps better your mobility and stability , Hirt explains.

Experts explain whether walking counts as cardio for reaping the heart-healthy benefits of exercise–and how to increase the intensity of your walking workout.

If you’re on a treadmill, try walking three miles per hour and crank up the incline until your heart rate hits zone 2. For some people, an incline of five is enough, Yu says.

An avid runner, she even had trouble walking up a hill. She was young and ate a healthy diet. Pearce never imagined she could have heart disease. But she did.