Head to Head Comparison: Smart Watch vs. Activity Trackers vs. GPS Running Watches

Garmin Forerunner 230 VS vivofit

Want to get more activity in during the day? If you walk into any fitness store, or grocery store for that matter, you can now buy an activity monitor like a Fitbit, Jawbone, or a smart watch like the Apple iWatch thinking it’s going to change your life. Activity monitors have become pretty complex: they measure steps, distance ran, sleep pattern, calories burnt, measure heart rate, read text messages and emails. But how do these activity trackers actually function?

Many of these activity trackers record movement using a digital accelerometer; this computer measures the swing of your hand and, through a mathematical algorithm, translates this into a step, a run, or even a jump. The same accelerometer measures sleep patterns as your body is more calm while you are sleeping. The sensors precision varies depending on it’s quality, that’s one of the reasons why the price ranges of these trackers can vary. The gold standard of movement measurements is GPS. These watches are based on satellite readings and can be very accurate depending on the price. Most of the higher-end running and activity watches use GPS and leverage this to map out precise locations, distances ran, speed, cadence, and even finding your way back to the starting point. These monitors, however, do have a problem in that cloud cover and tall buildings can get in the way of their readings but the sensitivity has improved a great deal.

In activity monitors like the Fitbit, heart rate is generally measured by light refraction: an LED shines against the skin and sensors measure the reflection of blood flowing through veins or capillaries. Mathematical algorithms are used to cancel out things like movement, sensor placement, and many other variables that lead to inaccurate measurements. These sensors have their limitations as they are dependent on prolonged contact with the skin and a lack of movement. Heart rate is most accurately measured through a chest strap. The strap measures electrical impulses created by the heart and transfers these readings to the watch. These measurements have been known to be almost as accurate as clinical heart rate monitors and can be used in almost any condition. The straps, however aren’t as comfortable to wear for prolonged periods of time and have been known to cause chaffing for different body types.

These sensors can be pretty small so they tend to be able to fit into almost any fashionable wristband. The issue has always been accuracy in measurement: many people don’t calibrate the accelerometer for stride length and their own  movement patterns (if the unit has the ability to measure it), and each person’s running patterns can vary too. The heart rate monitors can vary wildly depending on their placement, how still the person is, and sweat on the skin.

The ideal running and activity watch is something that measures with all four sensors. Thankfully most, if not all of the current brands in this market place have watches that can do this at a price between $150 to $350 depending on the added options you would like. Options can include: bluetooth connectivity, reading text messages, emails, social media, movement goal setting, and the list goes on. Before buying it’s important to factor in a few things:

  • Type of activity you’ll be primarily using it for: a lower cost alternative may work perfectly if you are monitoring light activities like walking and general movement. If you are thinking of running or more vigorous activity then a chest strap monitor and a GPS watch may be a better option.
  • Fit: This is more especially with the light-based heart rate monitors. The strap should fit snugly on the wrist without exposing too much of the sensors.
  • Fashion/style: it’s so very true that this matters. If you aren’t going to wear it then there’s no use in buying it.
About Chris Tse

I’m a scientist turned owner of Blitz Conditioning, a Fitness Columnist at CBC Radio on Thursdays at 8:20 am, and owner of Tse Social Strategy. Follow me on Twitter or Read my full bio.

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