Garmin sleep analysis – discovery journey (1 week)

Since Garmin released, as part of the Fenix 6 beta firmware (you can find that on Garmin’s forum), the on-watch sleep analysis I’ve been trying to understand how that compares with the previous sleep info provided by Garmin (and eventually to test this with the Polar Vantage V).

The feature in itself it’s nice from two perspectives:

  • the ability to see your sleep data on the watch, without the need for mobile or web. It would make sense (and probably that will happen) that this info will be extended beyond one night – say to look at the stats for the last week … like you see for steps for example
  • the scoring and the observations regarding your sleep – and some actionable data – that looks like getting in line with Polar or Oura are doing [I’m no longer familiar with what Fitbit is doing, since I don’t own a Fitbit device anymore]

Since this is still a beta feature, which is not reflected in the apps (mobile or web), it’s difficult to understand what options you have to understand the data, what’s the meaning of “balanced” or “refreshing” in the statements Garmin delivers. Therefor, I’ll document my data with pictures and other comments, every day for a period (one week), until Garmin comes with more clarifications on this feature.

Note: I noticed that the sleep duration displayed on the watch doesn’t include the awake time, which may seem awkward, since to me that is part of my sleep session as well … I’m not interested only in the other phases of the sleep.

Conclusion (after one week): the feature is nice, the ability to see the data on you watch is very useful (missed it so far, coming from Vantage V). The accuracy of measurements maybe could be improved, as I feel that the sensitivity is too high, at least for awake time (which increased a lot after changing the algorithms and also is high compared to Vantage V). Overall, when this will be promoted to the GCM and web app, I’d see the value of the feature even more.

Day 1 – first day felt like a reasonable assessment of my sleep, the start and stop moments for the sleep being reasonably accurate. Was the sleep refreshing? Maybe, it was ok, but nothing special … so the Quality “Fair” looks reasonable to me.

Day 2 – Second day, the sleep analysis was not that accurate, since one of the breaks early in the day was interpreted as being the wake up moment, ignoring the fact that I went back to the bed for the next hour.

Day 3 – Third night analysis reflected the poor quality of my sleep, which I feel is true … the body battery said the same, I feel the same. In terms of duration and wake up moment, it’s accurate. I don’t remember to being awake 17 minutes, that sounds a lot … maybe the algorithm is too “aggressive” with the collected data? Time will tell. Also “sleep stages unbalanced” means that Garmin will come up with some materials to mention how the balance is defined to educate the users, because expecting the end-user to know the “magic ratio” won’t help a lot.

Day 4 – after a busy day that started with one running session and two bike rides, I felt pretty tired in the afternoon and the late evening beer consumption didn’t help a lot on the quality of sleep. But let’s say that the score Garmin provided is kind of inline with my feeling.

Since I started wearing the Polar Vantage V, for night sleep measurements, I wanted to see how that looks compared with Garmin’s data.

Vantage V data for the Day 4

So, the sleep starts a bit earlier … which may or not have happen, that’s not that important since that’s 4 mins. The awake moment is a bit more accurate since I get off my bed at that moment, Garmin noticed when I turned off the alarm earlier with 6 minutes. On the other hand, what’s interesting is the fact that Polar also reports 29 minutes of sleep interruptions, similar to the Garmin awake duration (28 minutes) and the moments for interruptions look similar on the timescale. So, you might say that the sleep detection is not that different but only the reporting and data displaying is different. We shall see in the next days.

Day 5 – I felt like the sleep was much better and that was reflected in the score I got from the Garmin Fenix 6X; the same was confirmed by the Polar Vantage V worn on the right hand. Garmin took some of the period in bed reading as sleep, it usually does, but the difference wasn’t huge. The awake moment is correct (for both watches). The sleep duration is similar, but that’s only because Garmin started the counting earlier and that compensated the awake moments, since for now Garmin doesn’t report the awake time as being part of the sleep.

Polar’s snapshot looks similar – even the score is very close [82 compared with 83], obviously inviting Garmin to move the data collected on the watch to the web/mobile platform (I mean score and start/end moments to be presented for a weekly chart…anyway, there is time for that). The sleep phases duration is different, but I didn’t expect anything else.

Polar’s sleep details for the 5th night

Day 6 – I didn’t feel great after this sleep over night, I felt tired and wanted to sleep some more. With that, I’d say that Garmin really got it right. I’m still puzzled with the amount of awake time … I feel like this is way too much or Garmin is very sensitive now to all the moves I do. I looked at the measurements provided by Polar Vantage V and those look more pertinent in terms of awake time (or interruptions as they say).

Polar’s analysis looks decent and in terms of moments of interrupted sleep, they seem more accurate – at least with what I can remember.

Vantage V says my sleep wasn’t that bad – not great, but still…

Day 7 – I felt that my sleep was of good quality, not perfect and that’s reflected in a way by Garmin’s analysis. I didn’t wear the Vantage this night so I don’t have something else to compare with other than my feeling.

I will continue the discovery journey by adding more observations, in other posts, maybe try to correlate that with other info (for example from Polar Vantage V which I considered a very good device for sleep analysis).

Stay safe and sleep well !

Author: Liviu Nastasa

Passionate about software development, sociology, running...definitely a geek.

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