What’s the most common excuse people cite for not taking care of their health? “I’m too busy!” Yet even extremely busy people do find time to take care of themselves, and their strategies can help all of us get more out of our time.

That’s what I discovered while researching my book, I Know How She Does It: How Successful Women Make the Most of Their Time. I had women with demanding careers and kids at home keep track of their time for a week. The resulting “Mosaic Project,” a time diary study of 1001 days in the lives of professional women and their families, showed me half hour by half hour how women spent their time.

The good news? The vast majority of these busy women found time to exercise. About 90 percent did some exercise, and the average was over three hours a week— a little bit more than the two and a half hours of moderate aerobic activity per week that the Centers for Disease Control and Prevention (CDC) recommends we get.

These busy women also found time to sleep. The average in my study was 54 hours per week. If you do the math and divide by seven days in a week, you get just a little under eight hours per day.

They made time for downtime too. While the women in my study didn’t watch much TV, they did watch some, about 4.4 hours/week. They read as well, and went out with friends, and had family meals.

So how did they find the time? Partly it’s that Americans in general spend more time on sleep and leisure than we think; the annual American Time Use Survey finds that the average American sleeps 8.8 hours per day, and 96 percent of Americans engage in leisure on any given day.

But beyond that, taking care of yourself is what makes a busy life possible. So people looked at what time was available to them, and used it for these high-value activities. The people who exercised the most engaged in “functional fitness”— biking for errands or walking to the train station as part of a commute. For those who were stuck with a regular old car commute, many realized that exercising in the morning wakes you up and helps you power through the day. If family dinner can’t always happen, maybe family breakfast can help you start the day right. And getting enough sleep means committing to get to bed on time— setting a “bedtime alarm” if necessary to remind you to shut down the phone or computer and pick up a book or magazine for a few minutes until you drift off. When you get enough sleep, you wake up feeling able to take on anything.

If you’re trying to figure out where the time goes, try doing what the women in the Mosaic Project did: Keep track of your time for a week. Even the busiest person has open space. All you have to do is find it, and then choose what to do with it. There’s no better choice for that time than to take care of your health.

Laura Vanderkam is the author of "I Know How She Does It," "168 Hours," and "What the Most Successful People Do Before Breakfast" -- a paperback compilation of the bestselling ebook series, all from Portfolio/Penguin. Her website is lauravanderkam.com.