The 411 On Activity Trackers


Each year, the American College of Sports Medicine surveys fitness professionals around the world to identify the hottest trends in the industry. In 2016, for the second year in a row, activity trackers were the number one response. In fact, the annual sales of activity trackers doubled from 2014 to 2015, to over $1.46 billion. With such a massive amount of growth, and the devices appearing everywhere, we could all be well served by a look at the pros and cons.

The number one benefit most cite from activity trackers is a motivation to move more. When we are tracking our steps, it can become a very beneficial challenge to try and add more each day. Anything that encourages us to move more, be more active and burn more calories has the potential for a major impact on our overall fitness and health level.


The primary drawback, at this stage of technological advancement, is accuracy. Wrist trackers without a torso strap and transmitter rely on an optical sensor to estimate Beats Per Minute. These devices have been found to be substantially less accurate than devices with straps, especially at higher levels of exertion. In fact, there is now class action litigation (image above) against manufacturers of wrist monitors from deaths claimed to result from wearers reaching heart rates that were too high but being unaware because the device showed them to be at a much lower rate. This shortcoming would also underestimate your calorie burn as well. In the support page for the Apple watch, for example, you’ll find this verbiage-“Many factors can affect the performance of the Apple watch heart rate sensor”. Also you’ll see “Some anomalies may appear in the displayed data, resulting in occasional heart rate measurements that are abnormally high or low.” After listing a number of factors that can prohibit the wearer from seeing accurate data, the same page adds “If you’re not able to get a consistent reading because of any of these factors, you can connect your Apple Watch wirelessly to external heart rate monitors such as Bluetooth chest straps.”.

The second inaccuracy issue comes from steps being calculated by arm movement with many devices. A client using a battle rope, for example, can show adding 100’s of steps without ever moving from their tracks. Even riding on a bumpy road can add steps you didn’t take to your tally.

In conclusion, if you need or desire accurate heart rate feedback, a device with a chest strap and transmitter is the most accurate and safe, and your best bet. If you are only looking for something that may entice you to be more active, a wrist only wearable may very well be sufficient. As quickly as technology is changing, this topic may very well have new answers soon.

Jim Harris