Today’s wearable technology makes it easier than ever to track your activity levels, by counting the steps you take each day, for example. To the extent that you use that information to inspire and motivate you to keep moving—or to get you moving even farther than you might otherwise—wearable trackers can clearly be useful fitness tools. Of course, wearable devices often do far more than count (or estimate) the steps you take in a given day.
The technology is constantly improving and evolving, but depending on the device you own, your tracker might perform other functions, too, such as keeping tabs on your heart rate, counting the number of times per day that you take the stairs, and even letting you know how many hours of sleep you’re getting. Many trackers also provide an estimate of calories burned per day, but a recent, published study of the accuracy of these estimates revealed that this particular parameter should be taken with a grain of salt, if not viewed with outright disbelief.
The devices contain miniaturized versions of triaxial accelerometers, altimeters, heart rate monitors, and global positioning system (GPS) monitors. Data from these sources, in combination with proprietary algorithms, are used to estimate how many calories you have burned in a given day. But the accuracy of these estimates varies widely among trackers, and even the best leave something to be desired in the accuracy department.
Heart rate monitor functions and even step counters tend to be considerably more accurate. Some devices even incorporate sensors to monitor respiration, skin response, ambient temperature, and skin temperature. A 2015 study of devices available at that time concluded that while step count accuracy was fairly high for most devices, some also struggled to count accurately during certain erratic or strenuous activities.
Of course, the problem with any fitness device, whether it’s a high-tech wearable fitness tracker or a complete home gym, is that you have to use it if it’s to do you any good. Anecdotal evidence suggests that many wearable devices that were initially embraced enthusiastically are eventually left to gather dust.
To the extent that a wearable device helps to motivate you to walk, run, jog, sprint, in-line skate dance, or otherwise move your body, it’s probably a good investment in your longterm cardiovascular fitness. A recent large, long-term study conducted in Scotland, for example, used fitness trackers to examine the question of how many steps per day are required to provide significant protection from the risk of cardiovascular disease. Although it has long been assumed that 10,000 steps per day is an appropriate target for this purpose, this seminal study discovered that the real magic number is closer to 15,000 steps per day.
Postal workers, including desk-bound personnel and peripatetic mailmen, were monitored for various physical parameters known to be linked to heart disease risk. These included body mass index, waist size, blood sugar levels, and cholesterol profiles. Needless to say, postal workers who spent all day sitting were more likely to be obese, and to have other risk factors for heart disease. The mail carriers, who logged at least 15,000 steps per day, had significantly better risk profiles.