The good news is that a comprehensive new long term study has the answer.
Researchers from UK Biobank analyzed 88,000 volunteers and followed each patient for seven days, tracking their sleep and wake times as well as other metrics like heart rate, breathing, and sleep cycles.
They then followed these patients for an average of six years, checking up on their heart and circulatory health over this time, and published their findings in the European Heart Journal.
What they discovered was that a bedtime between 10pm and 11 pm was the magic hour, and was linked to lower levels of cardiovascular disease. This remained true even when the researchers accounted for factors like sleep duration and sleep irregularity.
Although the researchers cannot prove cause and effect quite yet, the results of their long-term study are striking. They believe the benefits of this sleep time are linked to the fact that it allows the body to follow natural circadian rhythms.
Study author Dr David Plans, working with the healthtech organisation Huma, said: "While we cannot conclude causation from our study, the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health.
"The riskiest time was after midnight, potentially because it may reduce the likelihood of seeing morning light, which resets the body clock."
Regina Giblin, senior cardiac nurse at the British Heart Foundation, said: "This large study suggests that going to sleep between 10 and 11pm could be the sweet spot for most people to keep their heart healthy long-term."