A correct amount of sleep protects the health of the heart. This is the conclusion of new research, conducted by scientists from the United States and the United Kingdom, which has found that the duration of sleep can influence a person’s risk of heart attack, independent of other heart risk factors, including genetic ones .
The study, which has been published in the Journal of the American College of Cardiology , describes the analysis of sleep habits and medical records of 461,347 people between 40 and 69 years who lived in the United Kingdom.
The data, which comes from the Biobank, included self-reports of how many hours the participants typically slept each night and health records spanning 7 years. It also included test results for risk genes.
Not much nor little
The analysis revealed that those who slept less than 6 hours a night had a 20% higher risk of having a first heart attack compared to those who slept between 6 and 9 hours. Those who slept more than 9 hours had a 34% higher risk.
The researchers also found that keeping sleep duration at 6 to 9 hours per night can reduce the risk of a first heart attack by 18% in those with a “high genetic risk” for developing heart disease.
“This study provides some of the strongest evidence that sleep duration is a key factor when it comes to heart health, and this holds for everyone,” says Celine Vetter, assistant professor of integrative physiology at the University of Colorado in Boulder and leader of the job.
Sleep duration is an independent risk factor
Previous studies had established links between sleep habits and heart health. However, most of those findings come from observational studies – studies that can only confirm links but cannot establish cause and effect. Because many factors affect both sleep and heart health,It is not easy to determine whether poor sleep promotes poor heart health or if poor heart health leads to poor sleep.
In the present study, the researchers tried to meet this challenge by using data from a large number of individuals, combining it with genetic research, and ruling out dozens of possible influencing factors.
In total, they adjusted the results to eliminate the potential effect of 30 factors that can influence both heart health and sleep. These factors include physical activity, mental health, income, education, smoking, and body composition.The researchers’ results showed that sleep duration was an independent risk factor for heart attack.
The researchers found that the risk of heart attack increased even more when people’s usual nighttime sleep differed from 6 to 9 hours.
People who slept 5 hours a night, for example, had a 52% higher risk of having a first heart attackthan those who slept between 7 and 8 hours. People who slept 10 hours a night had twice the risk.
Mendeleian randomization
Later, the researchers used a method called Mendelian randomization (MA) to confirm that short sleep duration was an independent risk factor for heart attack.
Mendelian randomization uses genetic variants to determine whether an observational association between a risk factor and an outcome is consistent with a causal effect.
The AM analysis showed that people with genetic variants that predisposed them to poor sleep had a higher risk of heart attack. ( Previous studies have discovered more than two dozen variants associated with short sleep duration.)
“This gives us even more confidence that there is a causal relationship here, which is the duration of sleep, and not something else, that influences heart health,” says Vetter.
Sleep, key to heart health
According to the Centers for Disease Control and Prevention (CDC), these are the best tips for getting a good night’s sleep:
– Go to bed and get up the same time every day, even on weekends.
– See enough natural light, especially at the beginning of the day.
– Avoid exposure to artificial light, particularly in the hours before sleep.
– Get enough exercise daily and avoid doing it near bedtime.
– Avoid eating and drinking in the hours before going to sleep, especially alcohol and foods rich in fat and sugar.
Experts hope their findings will raise awareness among clinicians, the public, and policymakers about the impact of sleep on heart health.
Referencia: Nicola Montano, Elisa Fiorelli, Eleonora Tobaldini. Sleep Duration and the Heart. Journal of the American College of Cardiology, Volume 74, Issue 10, 10 September 2019, Pages 1315-1316 DOI: https://doi.org/10.1016/j.jacc.2019.07.022
