How Much Data Do You Need?
Credit: Photograph by Justin Steele

1. You Want to Move More, and Lose a Few
If you don't have time for the gym but you want a nudge to move around more – or if , like me, you're curious to find out how active you are during the 23 hours a day you're not exercising – basic activity trackers are the way to go. From the Misfit Shine to the Fitbit, most depend on simple accelerometers that measure motion in three dimensions. A computer algorithm uses data from that accelerometer to make rough guesses about how many steps you've taken, how many calories you've burned, and how much time you've spent lying still – and, therefore, likely asleep.

Mobile apps and websites encourage you to set and pursue goals based on these numbers, like walking 10,000 steps a day, the minimum recommended by the American Heart Association. "That's super helpful for people looking for motivation," says Dr. Jordan Metzl, sports medicine physician at New York City's Hospital for Special Surgery. "It gives people some sense of what being active looks and feels like." Metzl says it can also help boost your so-called NEAT profile – your non-exercise active thermogenesis, meaning the calories you burn in everyday life.

The downside: These devices can't tell the difference between sitting on the couch and squatting 500 pounds, but, says Misfit founder and CEO Sonny Vu, that's not the point. "Basic trackers are for people who don't care about the details. They just want to know, 'What's a win, for me, today?'?"

In my own case, after discovering that I'm shockingly sedentary between workout sessions, it meant simply parking a little farther away from the kids' school, or heading to the grocery store on foot now and then. For my friend Alex Hochman, a University of San Fran­cisco career counselor who bought a Fit­bit last year, it meant chasing that 10,000-steps-a-day number with such success that it helped him lose 40 pounds in four months. "I feel naked now if the Fitbit isn't on me," says Alex. "When I get dressed, it's on my belt the rest of the day. My kids tease me, but when you're trying to lose serious weight, it helps you reach those incremental goals."

Your Tracker: Misfit Shine

The waterproof Shine uses a long-lasting battery that never needs to be recharged, and it's adjustable so you can wear it on your wrist while swimming, your ankle while spinning, or on your belt for walking or running. It also tracks how many hours you sleep.