Less Than 6 Hours of Sleep Boosts Cardiovascular Risk, Findings Show

Sleeping less than 6 hours a night can raise a person’s risk of cardiovascular disease compared with those who get 7 or 8 hours of sleep, according to a new study in the Journal of the American College of Cardiology (JACC). Unlike a host of studies on how sleep affects health, this one shows how poor quality sleep increases plaque buildup in the arteries, raising the risk of atherosclerosis, which can cause a heart attack or stroke.

“Cardiovascular disease is a major global problem, and we are preventing and treating it using several approaches, including pharmaceuticals, physical activity, and diet. But this study emphasizes we have to include sleep as one of the weapons we use to fight heart disease—a factor we are compromising every day,” senior study author José M. Ordovás, PhD, researcher at the Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC) in Madrid, Spain, said in a statement.

While diet and exercise long have been the mantra for those seeking to be healthy, the need to add sleep to the mix has gained traction in recent years. For the first time, researchers quantified the length of sleep and then matched patients with measurable levels of physical deterioration.

“This is the first study to show that objectively measured sleep is independently associated with atherosclerosis throughout the body, not just in the heart,” said Ordovás, who is also a director of nutrition and genomics at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

Several studies in recent years have connected the lack of sleep with a higher risk of cardiometabolic ills, including type 2 diabetes (T2D) and cardiovascular disease, due to increased inflammation and elevated blood glucose levels. Disruption of circadian rhythms causes people on the night shift to be more likely to have T2D, to weigh more, and to have high blood pressure.

The study also found that alcohol and caffeine consumption were higher in those with shorter sleep. A separate study published this week from populations in several major South American cities found an association between heavy drinking and cardiovascular risk in men.²

In the sleep study, researchers followed 3974 bank employees in Spain from the PESA CNIC-Santander Study, led by JACC Editor-in-Chief Valentin Fuster, MD, PhD. The team used imaging to examine the prevalence and rate of progression of subclinical vascular lesions in the population, whose average age was 46 years. Two-thirds of the participants were men and none had known heart disease.

Study subjects wore a device called an actigraph, which measures all movement for 7 days, to record their sleep. The research team then divided the population into 4 groups: (1) those who slept less than 6 hours, (2) those who slept 6 to 7 hours, (3) those who slept 7 to 8 hours, (4) and those who slept more than 8 hours.

All participants had 3D heart ultrasound and cardiac computerized tomography scans to detect heart disease. After risk factors were weighed in, those who slept less than 27% were more likely to have atherosclerosis throughout the body compared with those who slept 7 to 8 hours. Those with poor quality sleep were 34% more likely to have atherosclerosis than those who slept soundly, as measured by the frequency of movements recorded by the device.

Alcohol creates a “rebound” effect in many people, Ordovás said. "If you drink alcohol, you may wake up after a short period of sleep and have a hard time getting back to sleep. And if you do get back to sleep, it's often a poor-quality sleep.”

The dramatic effect of alcohol was seen in the second study, which was drawn from a population sample in 4 cities in Argentina, Chile, and Uruguay. A total of 37.2% of the population never drank, and 18.3% were former drinkers. Among men who were the heaviest drinkers, the odds of having >20% risk of cardiovascular disease was about twice as high as those who had never drank. The odds of having a history of cardiovascular disease was 50% lower in those with moderate consumption.

References

1. Dominguez F, Fuster V, Fernandez-Alvira JM, et al. Association of sleep duration and quality with subclinical atherosclerosis. J Am Coll Cardiol. 2019;73(2):134-144. DOI: 10.1016/j.jacc.2018.10.060.
2. Gulayin PB, Irazola V, Gutierrez L, et al. Association between drinking patterns and cardiovascular risk: a population-based study in the Southern Cone of Latin America [published online January 11, 2019]. J Pub Health. doi.org/10.1093/pubmed/fdy226.