Fitbit

[ted]

My son gave me a Charge HR for Christmas. Anybody here I can compare notes with ?

[Bob]

Youtube has some reviews. 

I thought about one but that was as far as I got.

[ted]

Mine seems to display false spikes in pulse. By and large it seems very accurate for my daily training, and my sleep and sitting rates of 40-50 and 50-55 respectively show correctly. But as a really siily example, during my piano playing this morning, it said I had spent several minutes in my peak zone with a maximum of 165. This is plainly absurd. An obvious cause must exist, but I'm not getting much sense from people on the fitbit forum.

Aside from these unexplained spikes, I think it is a very good aid to fitness.

[Petter]

But as a really siily example, during my piano playing this morning, it said I had spent several minutes in my peak zone with a maximum of 165.
Aside from these unexplained spikes, I think it is a very good aid to fitness.

must be cosmic interference?

[ted]

Here is the heart rate graph for the aerobic component of my usual daily training routine.



Here is the heart rate graph for yesterday morning's piano playing.


The stationary cycling one is pretty correct, I think, but the piano one is clearly very wrong. A maximum of 165bpm playing the piano is absurd. The Fitbit does not work for activities involving a lot of arm movement. Whether this is due to hardware or software I cannot ascertain and nobody on the Fitbit forum has yet given me a sensible answer.

[Bob]

Interesting graphs.

Is that connecting to a smartphone or a computer?  How long will it take in info like that?

[ted]

Mine transfers data every fifteen minutes via wireless. I understand the device itself can hold seven days continuous data without syncing with the computer. Once transferred, historical data is always available for analysis.

[Bob]

How does that measure your heart rate?  Just through the wrist?

[ted]

I gather that LED lights adjacent to the skin continuously detect expansion and contraction of capillaries. Algorithms are then applied to the data to calculate a likely pulse. I have no idea what the algorithm is but I assume it involves some sort of numerical smoothing. I have found the data for rest and training in general to be accurate, but clearly that for piano playing is wildly out. So far the Fitbit forum have not seen "fit" to tell me why.

[Bob]

Yep...
https://help.fitbit.com/articles/en_US/Help_article/Heart-rate-FAQs

Looks like it's probably the movement you mentioned. 

I wonder if that can be connected to a chest strap monitor....


How do you connect it to a computer?  It's all wireless, or does it have a spot to plug in?

[Bob]

Something about dominant hand, typing, writing, etc.
https://help.fitbit.com/articles/en_US/Help_article/How-accurate-is-my-Charge-HR?c=Topics%3AAccuracy&fs=Search&l=en_US&pn=1

If it helps.

[ted]

It comes with a small USB dongle, which it uses for syncing with the computer every fifteen minutes to transfer data. I soon found that this process interferes with the automatic sleep options on the iMac, so I just insert the dongle every so often as required. People who leave their computers on all the time wouldn't worry though.

The piano playing inaccuracy doesn't really bother me, as for other activities it is very accurate and helpful.

Thanks for the link. Step counts do not interest me at this stage, but I shall try the dominant hand option out of academic interest. All it does is decrease the sensitivity to movement, based on the assumption that the dominant hand moves more. In my case, this assumption is probably false.

[thalbergmad]

I bet your heart rate goes up when you are pushing that old lawnmower

Thal

[ted]

I bet your heart rate goes up when you are pushing that old lawnmower

Thal

That was one of the first things I recorded.

[Bob]

Are you leaving that on all day or just during certain time periods?

Then you connect it to the computer to transfer info?  Is that a website making the graph (info from the fitbit uploaded to a site) or is it software on the computer?

Still looks interesting.

[ted]

All day, but not while showering or swimming, although they say you can. It syncs every fifteen minutes via wireless. Combination of site and software I think, but that is a guess.