I got a H10 for just this 
But I’m thinking about switching to an Oura Ring as I usually don’t train late in the evening or eat late, so the difference between nightly and morning measurements should be negligible. My garmin however is not that accurate due to wearing a titanium bracelet instead if the silicone strap, which means that especially when laying down it can be the case that the optical sensor won’t rest against my skin perfectly.
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