Comment by OrwellianChild | Hacker News Reader

Comment by OrwellianChild | Hacker News Reader

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These are all worthy considerations for these trackers... I can only speak for the Fitbits, specifically the Charge 2 (which has a HR monitor too).

Fitbits have 2 measurement modes for sleep - normal and sensitive. Normal pretty much tracks me as sleeping like the dead for 8 hours each night (however long I'm immobile in bed). Sensitive, on the other hand, tracks much more detail and can tell when I'm restless, sleeping deeply, and even when I get up in the night and move around. I highly recommend the sensitive sleep setting for Fitbit users - it gives you more data to play with!

Fitbit recently re-worked the way they track sleep in its HR-monitor-equipped devices (Charge 2, Aria HR, etc.). It introduced more details (it was just tracking restless/deep before) and this upgrade greatly improved the sleep tracking for me. Before Sleep Stages, it would track only 3-4 hours of my sleep each night. Now, it catches the full 6-9 hours.

Now, all of this is to be taken with a grain of salt in terms of accuracy, but to compare among Fitbit users and to yourself over time, this information is incredibly useful!

The strongest example of the usefulness of this for me so far has been the effect of moderate alcohol consumption on the quality of my sleep. I am far more restless and get much poorer sleep after drinking just 1-2 beers on a full stomach. This has led me to cut back almost completely on alcohol and the quality of my rest has dramatically improved!

>The strongest example of the usefulness of this for me so far has been the effect of moderate alcohol consumption on the quality of my sleep. I am far more restless and get much poorer sleep after drinking just 1-2 beers on a full stomach.

I'm curious, did you not notice this before? I have an MS Band, but the sleep tracking seems similar to the new Fitbit tracking. It did give me some concrete data on how drinking affects my sleep, but that data wasn't really valuable because I already knew that drinking too much or too late would have a negative impact on my sleep because I felt tired the next morning.

For me, it was the difference between assumptions/inferences and repeatable measurements... Being typically human, I was able to be unobservant, post-rationalize my poor sleep, believe I still had the drinking constitution of a 20-year-old, and otherwise ignore the effects.

Having months of daily Fitbit records that I could look back on well after I forgot about my "rough morning" the following day drove the point home as only hard data could.

How do you know if it's "catching" anything other than noise? Have you done any kind of comparison against a gold standard method like a sleep study?

From what I can tell, none of these accelerometer-based methods work at all and the companies pushing these as sleep trackers are making false claims.

Like I said, accuracy isn't so much the goal... The readouts I get show pretty consistent measurements over time, which gives me enough confidence to compare them to other Fitbit users among my friends/family as well as to myself over time (see the alcohol anecdote above).

Setting the sensitivity to "normal" just raises the noise floor in their filter so high that it obscures the data.On sensitive, I've never had issues with it identifying "sitting" as "sleeping", yet it still effectively tracks my sleep (including periods of wakefulness immediately pre- and post- slumber in bed as well as mid-night disruptions that wake me up). This suggests that I'm getting pretty good data (though not equivalent to a sleep study with ECG/EKG equipment). In this case, "good" is good enough for my uses.

I've done a sleep study at a hospital to see if I was an actual insomniac or had sleep apnea. It turns out I slept like absolute crap at the study mainly because the thing they put up my nose tickled my nose hairs and the thing on my head was uncomfortable, so I just was restless the entire night.

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