Going to bed earlier could lead to oversleeping, which has been connected to various health issues, including heart disease (via Johns Hopkins Medicine). Perhaps more importantly, however, the CDC notes that not getting the right amount of sleep regularly can actually raise the likelihood of heart disease.
A 2021 study involved researchers tracking more than 88,000 adults over a roughly six-year period. Among the participants, 3,172 experienced cardiovascular events (e.g., heart failure, heart disease, or stroke). The data showed that those who fell asleep at either midnight or after midnight were the most likely to experience these. On the other hand, the group who experienced such heart-related health problems the least fell asleep anywhere from 10 to 10:59 p.m.
Although the study pointed to a later bedtime as possibly bad for one’s heart, there were also negative findings about going to sleep too early. While women were more likely to have heart issues if they fell asleep later, men who fell asleep before 10 p.m. were more likely to have heart health problems. With that said, neuroscientist and study co-author David Plans clarified that causation could not be concluded based on the study results (via NBC).