Published Tuesday 3 September 2019
By Catharine
Paddock PhD Fact checked by
Carolyn Robertson
The right amount of sleep is protective of
heart health. This was the conclusion of new research that found sleep duration
can influence a person's risk of heart attack, regardless of other heart risk
factors, including genetic ones.
In a recent Journal of the
American College of Cardiology paper, scientists from the
United States and the United Kingdom describe how they analyzed sleep habits
and medical records of 461,347 people aged 40–69 years living in the U.K.
The data, which came from the UK Biobank, included
self-reports of how many hours participants habitually slept per night and
health records covering 7 years. It also included results of tests for risk
genes.
The analysis revealed that those who slept
less than 6 hours per night had a 20% higher risk of a first heart attack in
comparison to those who slept 6–9 hours. Those who slept more than 9 hours had
a 34% higher risk.
The researchers also found that keeping sleep
duration to 6–9 hours per night can reduce the risk of a first heart attack by 18%
in those people with a "high genetic liability" for developing heart disease.
"This [study]," says senior study
author Celine Vetter, Ph.D., an assistant professor of integrative physiology at the
University of Colorado at Boulder, "provides some of the strongest proof
yet that sleep duration is a key factor when it comes to heart health — and
this holds true for everyone."
Sleep duration is an independent risk factor
Studies have been finding links between sleep
habits and heart health for some time now. However, most of those findings have
come from observational studies: these studies that can only confirm links but
cannot establish the direction of cause and effect.
Because many factors affect both sleep and
heart health, it is not easy to determine whether poor sleep makes for poor
heart health or poor heart health leads to poor sleep.
Vetter and her colleagues sought to meet this
challenge by using data from a vast number of individuals, combining it with
genetic research, and ruling out dozens of potential influencing factors.
Altogether, they adjusted the results to
remove 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 the further that people's habitual night sleep diverged from
6–9 hours.
Individuals who slept 5 hours each night, for
example, had a 52% higher risk of a first heart attack than those who slept 7–8
hours. Individuals who slept 10 hours per night had double the risk.
Analysis using gene variants for short sleep
The team then used a method called Mendelian
randomization (MR) to confirm that short sleep duration was an independent risk
factor for heart attack.
The MR analysis showed that individuals with
gene variants that predisposed them to short sleep had a higher risk of heart
attack.
Previous studies have uncovered more than 2
dozen variants associated with short sleep duration.
By using genetic variants, MR can determine
whether an observational link between a risk factor and a disease is consistent with
a causal effect.
"This gives us even more confidence that
there is a causal relationship here – that it is sleep duration, not something
else, influencing heart health," Vetter argues.
Sleep is key to heart health
According to the Centers for Disease Control
and Prevention (CDC), more than one-third of adults in the U.S. sleep less than
the recommended 7 hours per night.
The CDC recommend the following tips for good
sleep:
·
Go to bed and rise at
the same time every day, even at the weekend.
·
Get enough natural
light — especially earlier in the day.
·
Avoid exposure to
artificial light, particularly in the hours up to bedtime.
·
Get enough daily
exercise and avoid exercising near bedtime.
·
Avoid eating and
drinking in the hours before bedtime — especially alcohol and high fat and
sugar-rich foods.
·
If difficulties
persist, seek medical advice to help identify obstacles to sleep, including
other health conditions.
The latest research team hopes that its
findings will raise awareness among doctors, the public, and policymakers about
the impact of sleep on heart health.
"It's kind of a hopeful message,"
says first study author Iyas Daghlas, who is studying medicine at Harvard
Medical School in Boston, MA, "that regardless of what your inherited risk
for heart attack is, sleeping a healthy amount may cut that risk just like
eating a health[ful] diet, not smoking, and other lifestyle approaches
can."
"Just as working out and eating health[fully] can reduce
your risk of heart disease, sleep can too."
Celine
Vetter, Ph.D.
No comments:
Post a Comment