Results of a study of 116,632 people from 21 countries published online Dec. 5, 2019 in the European Heart Journal show that estimated total sleep duration of 6 to 8 hours daily is associated with the lowest risk of deaths and major cardiovascular events. Daytime napping is associated with increased risks of major cardiovascular events and deaths in those with >6 h of nighttime sleep but not in those sleeping ≤6 h/night.