How to know if a digital fitness monitor is worth the money

You can track calories, steps, and much more. But should you?

The latest trend in high-tech health puts control in the palm of your hand. It's called digital fitness monitoring, and it comes in the form of tiny gadgets that you wear or place in your pocket. "If you're already motivated to exercise or eat differently, the monitor is a great tool to track your progress and help you understand where you need to make changes," says Dr. Anne Thorndike, a preventive medicine researcher and assistant professor of medicine at Harvard Medical School.

Types and features

Digital fitness monitors (DFMs) come in wearable styles such as wristbands, watches, and pendants, as well as hand-held pieces you can clip onto a sleeve or slip into a pocket.

DFM features may be simple, such as sensors that track the amount of steps you take or calories you burn. Or they may be more sophisticated, with sensors that capture your heart rate, perspiration, skin temperature, and sleep patterns. Some DFMs have longer-lasting batteries, light-up screens, and alarms that vibrate or flash to remind you to be more active or announce that you've reached a goal. Others have satellite navigation, speed and pace sensors, and even weather gauges. Most have programs for a computer or smartphone that allow you to chart your progress.

What to look for

DFM prices increase with the amount of bells and whistles available. You may see one gadget for $25 and another for $750. The majority, however, are in the $50–$200 range. How much you spend is a matter of personal preference. "Sophisticated monitors can be fun, but all you really need to know is how many steps you're taking," says Dr. Thorndike.

She advises that you first determine what kind of information will help you reach your fitness goals, then consider if you're going to wear a DFM on your wrist or clip it onto your clothes. "And look for something that's easy to use and can be charged quickly," she says.

Making the most of a DFM

Before you set your fitness goals, wear the DFM to get a sense of how many steps you already take. "We tell people to shoot for 10,000 steps a day, but if you only take 2,000, you can set your first goal at 3,000," says Dr. Thorndike. Then use the DFM to see how you're doing throughout the day: if you're low on steps by dinner, take a walk afterward.

And consider fitness competitions with others using DFMs. Dr. Thorndike just completed a study that found young adults who used DFMs and engaged in competitions had a small but statistically significant increase in activity levels.