Is there a bedtime that is better for our health?
Research from the UK suggests that it does: going to bed between 10pm and 11pm appears to protect heart health and reduce the risk of cardiovascular disease. Although the researchers say the study does not show a cause-and-effect relationship, they attribute the results to the circadian cycle (our biological clock, the mechanism by which the body regulates day and night) and point out that sleep time is a potential cardiac risk factor, independent of other factors.
To reach that conclusion, the researchers followed nearly 88,000 volunteers with an average age of 61 for nearly six years. Information about the right time to go to sleep was collected through a wrist device for seven days, in addition to answering questionnaires about lifestyle, health and demographic conditions.
In addition, in the period, the researchers analyzed the diagnostic data of cardiovascular diseases: heart attack, stroke, heart failure, among others. The results were published in the European Heart Journal Digital.
During follow-up, 3.6% of participants developed some cardiovascular disease. The researchers adjusted for data such as age, sex, sleep duration, sleep irregularity (varying sleep and wake times), whether the person was daytime or nighttime (based on self-report), smoking, body mass index, diabetes, blood pressure and cholesterol levels.
The results showed that the risk of cardiovascular problems was 25% higher among those who went to bed at midnight or later and 24% higher in those who went to bed before 10pm, compared with those who went to bed between 10pm and 10:59pm – who had 12% risk.
Although several studies investigate sleep duration and cardiovascular disease, the relationship between sleep time is still poorly explored and this study evaluated sleep onset and wake time objectively, rather than this information being self-reported.
“It is already well established that sleep deprivation increases the risk of cardiovascular, metabolic and mental health diseases. But what is new in this work is that it followed the population in real life by analyzing the pattern of sleep and wakefulness and compared it to an objective marking, which is sleep timing, the time it happens”, said Leonardo Goulart, a neurologist specializing in sleep medicine at Hospital Israelita Albert Einstein.
According to Goulart, it is difficult to talk about the ideal time to sleep because people vary in the functioning of the circadian cycle, of the biological clock.
It works like this: for some people, the brain will send the sleep schedule later and the wake schedule later – these are the afternoons. For others, the biological clock will prepare the body for sleep and wakefulness earlier – these are the morning ones.
Intermediates are those whose sleep time is between morning and afternoon. “But there is a group of people who are morning people, but because of their habits [rotinas e escolhas profissionais e pessoais]go to sleep later and later and end up being sleep deprived, because they can’t sleep until later”, he says.
Those people who are delaying the arrival of sleep and becoming more and more afternoon, can develop mental health and cardiovascular problems.
“Sleep timing varies according to each person’s genetic manifestation. If the person plans their lifestyle according to their profile, [vespertino ou matutino] naturally, everything is fine. The problem occurs when the misalignment between the biological time and the desired to fulfill social/occupational functions generates a long-term sleep deprivation”, said Goulart, who stressed that the recommendation is for the person to always have a balanced life and respect their biology. and the amount of sleep the body is asking for.
“Sleep is irreplaceable. You can’t replace sleep with medicine, healthy eating or sleeping all day on the weekend. The cellular damage caused by sleep deprivation, which causes increased inflammatory activity, for example, is gone. The important thing is to respect each one’s bedtime,” he concluded.