There seems to be quite a lot of information about why <7 hours sleep is bad for you, but I'm more interested in why sleep >=8 hours is associated with increased mortality.
I read "Why We Sleep" but unfortunately it didn't answer this question. The association could be correlational but it's been replicated too many times for me to believe that there's not something more fundamental. Perhaps there's a hormetic effect that's blunted by too much sleep similar to how HGH is bad for longevity?
See for example https://www.ncbi.nlm.nih.gov/pubmed/29790200 (an interesting study in itself).
I read "Why We Sleep" but unfortunately it didn't answer this question. The association could be correlational but it's been replicated too many times for me to believe that there's not something more fundamental. Perhaps there's a hormetic effect that's blunted by too much sleep similar to how HGH is bad for longevity?