Sleep May Play Important Role in Heart Health
A good night's sleep boosts the benefits of a healthy lifestyle on the heart, according to a new large study from the Netherlands published in the European Journal of Preventive Cardiology on Wednesday.
The researchers found that not smoking, regular exercise, a healthy diet, and moderate alcohol consumption protects against cardiovascular disease (CVD).
However, they also found sufficient sleep (defined as 7 or more hours a night) further increases the heart benefits of these four traditional healthy lifestyle habits.
Their analysis suggests the effect of sufficient sleep on heart-related deaths could be as strong as not smoking.
Cardiovascular disease (CVD) is a general term for diseases of the heart or blood vessels, such as coronary heart disease, stroke peripheral arterial disease, and aortic disease.
Principal investigator Monique Verschuren, of the Dutch National Institute for Public Health and the Environment, says in a statement the importance of sufficient sleep "should be mentioned as an additional way to reduce the risk of cardiovascular disease."
She and her colleagues conclude that the public health impact of sufficient sleep "could be substantial."
"It is always important to confirm results," says Verschuren, "but the evidence is certainly growing that sleep should be added to our list of CVD risk factors."
Short sleep has been linked to obesity, high blood pressure and other factors directly associated with cardiovascular risk, say the researchers.
Another study published recently also suggests that sleep could be key to preventing type 2 diabetes.
In their large population follow-up study, Verschuren and colleagues found that the combination of the four traditional lifestyle factors was linked to a 57% lower risk of both fatal and non-fatal CVD, and a 67% lower risk of fatal events.
But when they added sufficient sleep to the four factors, the heart benefit increased further: the risk of composite CVD was 65% lower and the risk of fatal events was 83% lower. They defined "sufficient sleep" as 7 or more hours per night.
If all the participants of the study were to follow all five healthy lifestyle factors, in theory, 36% of fatal and non-fatal CVD and 57% of fatal events could be prevented or postponed, conclude the researchers.
The large study is called the Monitoring Project on Risk Factors for Chronic Diseases (MORGEN). The participants consisted of 6,672 men and 7,967 women aged from 20 to 65 who were free of CVD when recruited. The study followed them for an average of 12 years.
Information about participants' lifestyle, such as alcohol consumption, physical activity, diet, smoking and amount of sleep was recorded between 1993 and 1997. They were then followed through national hospital and mortality registers.
The results, as expected, showed that each of the four traditional lifestyle factors (not smoking, healthy diet, exercise and moderate alcohol) was tied to reduced CVD risk.
For instance, participants who on enrollment were following a healthy diet, doing enough exercise and drinking only moderate amounts of alcohol, had between 12% lower risk for fatal and non-fatal CVD for a healthy diet, to 43% for not smoking. The risk reduction for fatal CVD ranged from 26% for doing sufficient exercise to 43% for not smoking.
The data for sleep duration also showed a link with CVD risk. For instance, sufficient sleep alone (without the other factors) reduced the risk of fatal and non-fatal CVD by around 22% and fatal CVD by about 43% compared with insufficient sleep.
The analysis showed that the effect of sufficient sleep was the same as not smoking: they were both strongly and similarly inversely linked with fatal CVD.
Verschuren notes that 7 hours is the average sleep duration that "is likely to be sufficient for most people".
She and her team carried out an earlier study on sleep quality that found people who did not get sufficient sleep (slept less than 7 hours) and rose feeling unrested in the morning had a 63% higher risk of CVD than people who had sufficient sleep. But those who woke feeling rested, even if they did not get the required 7 hours of sleep, did not have the increased risk.
A report published in 2011 by the Mental Health Foundation suggests that insomnia is a major health concern in Britain. Overall, the report concluded that poor sleep increases the risk of poor mental health. The authors also said that the amount of sleep a person needs varies, and what is important is for people to find out how much they need and make sure they get it.