Count the number of hours you sit each day. Be honest.
"If you commute an hour in the morning and hour after work — that's two hours, and if you sit at an eight-hour-a-day desk job that's 10," says epidemiologist Loretta DiPietro of the Milken Institute School of Public Health at George Washington University.
"Then you come home at, say, 6 p.m., eat dinner and crash into your recliner for another three to four hours," says DiPietro. "That's 13 to 14 hours of sitting."