Who knew?  A study of women ages 50-79 found that those who averaged 6 hours of sleep or less per night had up to 20% greater risk of stroke – no surprise there.  But those who slept more than 9 hours nightly were 60 to 70% MORE likely to have a stroke!  Are they depressed, on medication?  Aiming for 7 to 8 hours seems safest.