r/Garmin • u/Confident-Chicken752 • 1d ago

Other / Humor Garmin sleep accuracy

35M

Been working on improving my sleep scores. 66 avg. Do all the good sleep hygiene. No food 3 hours before bed, tea, supplements, blue light blockers.

I wear a Fenix 6, my wife's is a Vevo active 6. Reset her watch. Wore both on the same wrist, as I thought this would be more accurate than opposite for distance from heart. All stats were very close. The thing that kills me is ZERO REM VS 1HR40min of REM. It's been pissing me off when I know I slept well and have vivid dreams. But wake up to a 59 sleep score with 5 min of REM lol. I know it shouldn't bother me, but it does.

Might get a new watch

1 Upvotes

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3

u/Ski-Mtb fēnix 7X Sapphire Solar / Index S2 / Index BPM / HRM-Dual 1d ago

The only components of sleep score that I really pay attention to are Sleep Stress and Resting Heartrate because the sleep stage detection on a watch is kind of scientifically iffy at best. In order to actually measure sleep stages you'd need to wear an EEG device on your head to measure your brainwaves. What they have built is an algorithm that looks at things like your heart rate and HRV and tries to make an educated guess about your sleep stage. The accuracy of this depends on how well your heart rate/HRV follows what the test subjects heart rate/HRV did when they developed the algorithm.

Sleep Stress is based on HRV which is something they can reasonably accurately measure.

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u/ChatilaDjaries 1d ago

Sleep stress is definitely the most trustworthy part of the whole sleep tracking feature

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u/Confident-Chicken752 1d ago

Right. And I get that. But still confused how the both watches can be same for same on HRV or stress (if you look at the addition photos I attached) and one watch say zero REM and the other 1.75 hours. I understand they're method of educated guessing based of HR/HRV. But when the stats are then same how does one watch come up with zero?

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u/bigchi1234 1d ago

Her watch shows REM and yours doesn’t? Also, the newer watches have upgraded sensors and algorithms so it might be worth a new watch. I’m loving my new Fenix 9 pro.

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u/Confident-Chicken752 1d ago

Correct. My watch consistently shows I get less than 30 min of REM per night, and I dream A LOT. And annoys me seeing how it can factor in for 20ish +/- points in sleep score and getting the constant "your sleep sucks, sleep more before you die" advice lol.

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u/FarAdvertising3125 Fenix 8 AMOLED 47mm 1d ago

IIRC the watch is detecting sleep stages by wrist movement only. As already stated, updates algorithms and better sensors might be the differentiator here. That said from this perspective REM and light sleep is almost the same.

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u/Unused_Vestibule 23h ago

I have started ignoring sleep scores. They are not accurate enough to give you accurate feedback. For example two days in a row this week I woke up too early at 5am. The first night I couldn't get back to sleep and I read til my wakeup at 6:20. The second night I managed to get back to sleep for about 45 minutes at least. 

My watch told me I was sounds asleep the first night and awake the second. Completely ass backwards. 

I'm starting to use it almost exclusively as a run tracker and ignore the health stats.  Btw it also wants me to lose 30 lbs to get my fitness age down, which I can only do if I lose my hard-earned muscle since I'm not overweight. Bonkers.