Nothing beats a good quality sleep -- but heart-smart people should also be mindful of the time they go to bed, reveals a new study.As it turns out, falling asleep past a certain interval can significantly increase your risk of heart disease, researchers from London health tech company Huma have discovered.Those with an earlier bedtime aren't much better off either, the new study published Tuesday in the European Heart Journal — Digital Health has uncovered. Keep scrolling to find out what the heart-health sweet spot for falling asleep is.Best BedtimeAccording to the new research, the best time to go to sleep heart-health-wise is between 10 and 11 p.m. This goes for both sexes, although there is a bit of a difference -- we'll get into that in a bit. Falling asleep any later, whether it's within an hour or more, increases the cardiovascular risk by different percentages, depending on how late you turn it.Specifically, a bedtime between 11 and 11:59 p.m. raises the risk of heart disease by 12 percent, with the percentage jumping to 25 for those dozing off at or after midnight. Meanwhile, falling asleep before 10 p.m. ups the cardiovascular risk by 24 percent.“The body has a 24-hour internal clock, called circadian rhythm, that helps regulate physical and mental functioning,” explained neuroscientist David Plans, study co-author and head of research at Huma. “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.”Sleep DataThese results were obtained through an extensive analysis of biomedical data from a little over 88,000 adults with an average age of 61, who were tracked for a period of around six years. The data came from UK Biobank, a biomedical database hosting information about more than 500,000 volunteers aged 37 to 73 and recruited between 2006 and 2010, NBC is reporting.For the purpose of this study, the authors used data gathered from accelerometers the participants wore on their wrists for seven days, which recorded when they moved and helped gauge their bedtime and waking up schedule.As the authors point out in their paper, "accelerometers provide an alternative tool for measuring sleep parameters objectively," as opposed to questionnaires, which is the standard method in sleep research.Women Vs. MenDuring the six-year follow-up period, 3.6 percent of volunteers suffered cardiovascular events, such as strokes, heart attacks, or heart failure. According to the study, the highest number of cardiovascular incidents occurred in people falling asleep at midnight or later. Conversely, the lowest number was recorded in those with a 10-10:59 p.m. bedtime.Interestingly enough, there was a notable difference in the bedtime linked to the greater heart risk for men and women. In women, the cardiovascular risk was higher for volunteers going to bed later. However, in men, the situation was reversed, with the risk being more pronounced in those falling asleep before 10 p.m.Sleep & Cardiovascular DiseaseThe findings reinforce the knowledge that sleep is a risk factor in cardiovascular disease, points out Dr. Francoise Marvel, an assistant professor at Johns Hopkins Medicine in Baltimore, who was not involved in the study. Just like bedtime, sleep duration is also important, previous research indicates.According to the American Heart Association, people who sleep less than six hours are at risk for hypertension, which is a major cardiovascular risk factor.Nevertheless, "there is no evidence to suggest at this point that improving sleep will effectively reduce cardiovascular events," says Marvel, who is co-director of the Johns Hopkins Digital Health Lab."Cardiovascular disease (CVD) continues to be the most significant cause of mortality worldwide, with an estimated 18.6 million deaths each year," the Huma researchers write in their paper."Evidence suggests circadian rhythm disruption could be an understudied risk factor for CVD, and that prolonged misalignment of circadian rhythms is associated with elevated blood pressure, reduced sleep quality, increased risk for cardiovascular disorders, and may also stimulate atherosclerosis, providing a possible biological mechanism for increased cardiovascular risk," they show in the study.