Think about all the time you’ve spent on your feet over your adult life. Walking through grocery store aisles–again and again, milling about at work receptions, chasing after kids, wearing a path between fridge and stove and sink and dining table. So maybe this statistic shouldn’t be surprising: By the time women reach 50 we’ve walked more that 40,000 miles.

But that is really a lot of miles. That’s like hoofing it from Portland, Maine to San Diego 13 times, or once every 4 years. No, even better: That’s like trekking around the globe nearly twice. It wears us out just thinking about it.

This little factoid was coughed up by a U.K. shoe company called Hotter, which did a study of 1,000 women over age 50. Obviously there’s been some major extrapolating to get the 40,000-mile figure for a lifetime on so slim a sample, but we’ll roll with it because, in general, we recognize that women do a lot more than they get credit for. Maybe that applies in the walking sphere as well.

In the same study, researchers found that the women took 51,330 steps-—or approximately 24 miles—over the average week. “As the study shows, women are on the go—and on their feet—for a lot more time than they realize,” says Claire Reynolds from Hotter.

“It’s inspiring to see how many women of this demographic refuse to be defined by their age and live life at full pelt and grabbing the opportunities that come their way.” You’re damn right!

Read More: It’s Never Too Late: Getting in the Best Shape of Your Life After 50

Is Walking Enough Exercise?

We love walking as an exercise. It’s so easy to do, doesn’t cost anything to get into and, in general, helps keep you in shape and your mind from frying with stress.

But is it enough to really make a difference in your fitness level? Certainly walking is having a moment with all the Fitbit-like devices tracking our every stride. The average American walks between 3,000 to 4,000 steps a day, but that’s not saying much since we’re pretty unfit as a nation. The gals in the study were taking an average of 7,300 steps per day. That’s the way to show them! So reaching the standard goal of 10,000 a day (who came up with that number anyhow?) will certainly make you fitter.

The average pace of walking is 100 steps per minute. Therefore, 10,000 steps would take one hour and 40 minutes. This doesn’t mean you need to devote that much time to trekking the trails. You get walking points when you go from the parked car to the gym, to the office, or even to the…um…ice cream shop.

But to get more out of your walking, pick up the pace. According to the Centers for Disease Control and Prevention, the range for moderate intensity activity is between 2.5 to 4 miles per hour. A study of more than 50,000 adults in the U.K. found that people who walked regularly at an average or quick pace were 24 percent less likely to die from heart disease when compared to slow walkers.

Whew! This is a lot of math for a NextTribe story. Now we want to do the calculations on how much we need to walk per day to make it to the moon by the age of 80. Any math wizzes out there?

Read More: 8 Women, 6 Days, 116 Miles: A Walk to Channel the Spirit of Harriet Tubman