Get at least 150 minutes of exercise a week, even if it’s in 10-minute chunks.

No excuses: Need motivation to exercise? Find a friend who loves to walk.

RODALE NEWS, EMMAUS, PA—Exercising 150 minutes a week greatly reduces a woman’s risk of dying from breast cancer, according to a study published in the April edition of the journal Medicine & Science in Sports & Exercise.

THE DETAILS: University of South Carolina researchers studied the exercise patterns of more than 14,000 women ages 20 to 83 years old who had no previous history of breast cancer. The participants were tested on treadmills to check their fitness levels between 1973 and 2001, and monitored for breast cancer deaths through 2003.

The researchers found that women on the low end of aerobic fitness were 3 times more likely to die from breast cancer than the women in the fittest group. Women who exercised moderately—for instance, walking 150 minutes or jogging 75 minutes total each week—saw a 33 percent lower risk of dying from breast cancer, while those in the high fitness group (exercising moderately 300 minutes a week, or vigorously, such as jogging or taking aerobics, 150 minutes a week) enjoyed a 55 percent lower risk.

WHAT IT MEANS: Exercise is a key weapon against cancer. And if you dedicate at least 150 minutes a week to walking, jogging, kickboxing, or some other aerobic activity, you’ll likely see all sorts of other improvements, too, such as lower blood pressure and cholesterol, and a lower risk of diabetes and cardiovascular disease. Another likely benefit of hitting the 150-minute target: better sleep.

Here’s how to step up your exercise program without totally overhauling your schedule: