FITNESS TRACKER RELIABILITY

A couple of years ago my wife gave me a Fitbit for Valentine's Day.  She loves me so much that she wants me to live longer and healthier.  But it may be that she is of the opinion that I don't have enough life insurance and that she thinks I'm worth more alive than dead. (JK!)

Anyway, I was flattered of course at the thought yet a little perturbed.  I told her she didn't need to spend that much on a Valentine gift and that there were other gift options she could have given that would've been more than sufficient -- I mean way more. (JK!)  So the thing laid in its box unopened for three weeks while I thought about taking it back and getting something less expensive.  But I thought better of it because I remembered something Confucius said: "Man who rejects gift from wife will sleep with dog." -- or something like that.

So one Sunday afternoon I looked over on the lampstand next to me and saw the thing still there and decided to open it.  I read the little instructions and went to the Fitbit website and got it cranked up.  As you well know, like other fitness tracking devices it measures steps walked, heart rate, calories burned, miles run, and stairs climbed.  It's even a stopwatch.  Can do everything but cook you a good plate of red beans and rice.

The first full day I wore it I was hooked.  i was already regularly walking and exercising but I now became very conscience of how many steps I made in a day.  My goal was 10,000 steps a day, and still is, and is rather ambitious for anyone who works inside in an office setting.  But I found myself walking even more, parking further away, and getting out of an office chair to walk more frequently.

I wondered how accurate it was so I measured my own steps over a prescribed distance and checked my heart rate by feeling my pulse over a minute.  It seemed to be pretty accurate.

But I just read about a research study that shows that the fitness tracking devices are not very accurate when it comes to energy expenditure, with letting you know how many calories you've burned.

In the study they looked at seven devices:  Apple Watch, PulsOn, Microsoft Band, Fitbit Surge, Basis Peak, Mio Alpha2, and Samsung Gear S2.

The activities tested were sitting, treadmill walking, and cycling.  A calorimeter was used to test calories burned.  The devices were more accurate during cycling and less accurate during walking.  Other factors associated with high device error were male sex, higher BMI and waist circumference, darker skin tone, and higher levels of activity intensity.

The most accurate devices for measuring heart rate was Apple Watch (best), PulseOn, and Microsoft Band.  The least accurate (7-9% error rate) was Basis Peak, Fitbit Surge, Mio Alpha 2, and Samsung Gear S2 (worst).

Interestingly, none of the devices could accurately measure energy expenditure or calories burned.  The least error rate came in at 27%!  The worst error rate was a whopping 92%! (Samsung).

The researchers are mystified as to why there's such a high rate of error on measuring calories burned but they think it might have something to do with each device having a proprietary algorithm for calculating energy expenditure that cannot match such a wide variety of people that use the devices.

So in a nutshell, the devices do a pretty good job of measuring heart rate but the recommendation is not to put a lot of faith in their ability to tell you how much energy you've burned.  In other words if your device says you burned a good bit of calories at some point in the day, don't think you "have room" to scarf a couple of doughnuts and wonder why the scale the next morning went the other way.

And if you happen to be given a fitness tracking device for Valentine's Day along with a box of chocolates then be thankful, tell him or her so, put it on, and start walking -- but only after you eat the chocolate.

Stay fit!

P.S.  As we get older our IQ decreases.  But you can lessen the decrease by engaging in resistance training (weights or bands) and aerobic activity (walking, biking, etc.).  There's a study on that too!