You’ve heard it before: walking is a good-for-you, non-impact aerobic exercise. Now a cardiovascular health study says that walking a significant amount every week can dramatically reduce your risk of developing heart disease.

The study, recently published in Chest, placed 133 sedentary, overweight adults with high cholesterol into four groups: walk 12 miles per week; jog 12 miles per week; jog 20 miles per week; no exercise. At the end of the seven-to nine-month study, the three exercise groups had significant improvements in cardiovascular and physical fitness, while the non-exercisers did not. Increasing the intensity of exercise (from walking to jogging) didn’t result in substantial changes in cardiovascular fitness, but the length of time spent exercising did, leaving the researchers to conclude that the amount of time spent exercising is more important than the exercise intensity. Based on this study, they recommend walking a minimum of 12 miles per week, or two miles six days a week, to improve cardiovascular health and lessen your risk of heart disease.