Elite athletes have always been data fiends, recording their speed, heart rate, and other workout information, often with the help of a personal trainer. Wearable fitness trackers, particularly the newest, most sophisticated models, are making that kind of record-keeping available to ordinary people.

Many of the latest models we reviewed worked well, but our testing found that none of them are foolproof, especially when you go beyond straight-forward metrics such as heart rate. So if you want to track a hard-to-measure variable such as calories burned, it’s best to use the readout as an estimate rather than an excuse for a second piece of pie.

The Fitbit Surge rates as one of the best fitness trackers
The Fitbit Surge is one of the best fitness trackers in our tests.

The top-rated Fitbit Surge, $250, is a good choice if you want lots of workout data combined with some smartwatch capabilities. In addition to counting steps and telling time, it comes equipped with a GPS mode, a highly accurate heart-rate monitor, and a large, easy-to-read display. It can also notify you when you receive a call or text on your smartphone.

For those willing to do without GPS data and phone notifications, the $100 Fitbit One is a bargain. The device, which clips to your clothing, capably counts steps and notes changes in elevation, useful if climbing stairs is part of your routine.

The least expensive tracker we tested, the Jawbone UP Move, $50, got dinged in our Ratings in part because it doesn’t have a display; to review all of your data, you have to download a free app to your mobile device. But it works well as a no-frills step counter, providing accurate info and syncing easily with a smartphone.

In addition to having their own apps, most trackers can coordinate with health apps such as MapMyRun. Some also work with companion products. The Withings Activité Pop, for example, has a bathroom-scale sibling, the Smart Body Analyzer; both feed data to a Withings health app to provide a fuller view of your fitness.

Privacy Alert
Like websites and mobile apps, fitness trackers might share personal data with manufacturers and software providers. To find out what information is collected and how it might be used, you should read the permissions section in the app’s description and the privacy policy on the manufacturer’s website.

Beyond Step Counting

All fitness trackers count steps, but many do more. Here are additional features you should look for.

FeatureWhat It DoesOur Take
GPS

High-end fitness trackers use a GPS mode to provide a more accurate picture of how far you have run, information also needed to calculate your pace.

It's handy, but you can get the same benefit by carrying your smartphone, which has a GPS function, and activating a free app such as RunKeeper.

Heart-Rate MonitorSeveral trackers are good at measuring heart rate at the wrist, limiting the need for the chest straps that serious athletes have used during workouts. Some trackers also record resting heart rate throughout the day.This feature is useful for data-oriented runners who want to stay in a certain heart-rate zone.
Stair TrackingDevices with altimeters can detect stair or hill climbing by measuring minor changes in elevation. (About 10 feet equal one flight of stairs.)

It's useful because hill climbing is a great way to boost a the intensity of a workout.


3 Tips to Get More Action

The best fitness tracker can motivate you to get fit
  1. Use the social functions. Much like a jogging partner or friends at the gym, the social features built into fitness-tracker apps can motivate you to get off the couch and out the door. You can use them to share workout results, receive notifications when one of your pals goes for a run, and set up group challenges, such as trying to reach a certain number of steps over the weekend.
  2. Find third-party apps. Most fitness trackers have companion apps that make it easy to review your workouts and monitor your progress. But there are other options for you to explore. MyFitnessPal, for instance, can use data from your fitness tracker to evaluate your exercise and food intake, which is particularly helpful if your goal is to lose weight.
  3. Preserve your battery. A tracker may work for a few days or even two weeks between charges. To extend battery life, you can remove alarms, turn off Bluetooth connectivity until it’s time to sync the device with your phone, and shut off the display when you’re inactive. (Note: Most trackers use a proprietary cable for charging, so try not to lose it—unless you view shopping as exercise.)