Customer Reviews for Garmin - Index Sleep Monitor Size: S/M - Black - (2025)
Customer Rating
1
Awful
on March 5, 2026
Posted by: Athleticguy
I bought the first one, and it was too small. Garmin made it right and replaced it for the right size. The large one had a defective sensor that never worked, so I sent it back. Contrary to some reviews it was really uncomfortable to sleep with because you either have to have it too loose so it slips off or if you secure it normally it pinches a nerve and cuts circulation off of arm. Garmin really needs to get on the ring bandwagon to monitor sleep without having to wear your watch. Now I don't monitor it because Garmin has no viable or good options and will not integrate oura or any other ring data into their app.
I’m a Garmin guy. This was an easy add and I really like the data. However, it assumes that once you put the band on your arm that you are ‘asleep’ and they you are ‘asleep’ until you take it off. Once you know that, it’s easier to calibrate reality. But I’m glad I purchased it. Would have been 5 stars if it was more intuitive.
Set up according to package directions. Synced with Garmin Connect app. Wore the band for two nights as directed. Zero sleep data was recorded. Even if the band DID work, the fact you have to tell it your "bed time" is ridiculous. Plenty of brands have sleep monitoring that detect this, and most people do not go to sleep at the exact same time every night. Will be returning.
If you don't already have sleep tracking, maybe ignore my review. Otherwise... I have a Forerunner 255; it does sleep tracking and myriad other things. For some unknown reason, I thought I would get better, richer, more accurate sleep-tracking info with the Index Sleep Monitor. I think I now get skin temperature that I didn't have before; that is about it. I thought the Smart Alarm would be cool; it would wake me at a magically ideal time. On the max setting, the alarm vibration is barely enough to wake me, and it is always at the latest time in the smart window, so I don't know that it has ever woken me differently than my FR255 would have. Anyways... I will keep using it, since I bought it and it works, but I won't bother to take it when I travel -- that is the indicator whether it was something I really need or not. I don't.
Accuracy seems better than the Garmin watches but hard to do a direct comparison. Very disappointed with comfort - there is a 3" long hard plastic rod used to adjust band tension that gouges my arm occasionally. There has to be a better way to adjust tension.
Sleeping with a watch to track sleep can be a bit intrusive, especially with the size of the Garmin watches. The Index Sleep Monitor removes that intrusiveness and allows for a better night's sleep. I have found the device provides data that is a bit more accurate. Not a single complaint about the device outside of the battery. It's good but just OK.
The sleeve provides the most accurate sleep data than two other pieces I own and use, both watches. It provides O2 levels, body battery, and HRV. It's the product I've been looking for a couple of years. Highly recommend it.