Mar 2, 2019 5 min read

Restless nights and lack of sleep may not just be leaving your tired and irritable. A new study shows it may also put you on the path to heart disease.

The study published in the Journal of the American College of Cardiology shows that people who slept less than six hours a night or who slept poorly were at higher risk for hardening of the arteries.

Researchers at the Mount Sinai Heart Center monitored the duration and quality of sleep of nearly 4,000 healthy men and women with an average age of 46 over seven nights. Then, they gave them physical exams and ultrasounds to measure blood flow in their vessels. Results showed that compared with people who slept seven to eight hours per night, those who slept less than six hours were 27 percent more likely to have a higher amount of plaque in their arteries and had markers of inflammation in their blood.

Those who moved the most during sleep also had higher amounts of plaque compared to people who slept soundly.

Some medical experts think the results pose an interesting situation much like “the chicken and the egg” conundrum.

“Is lack of sleep a marker of developing atherosclerotic disease or is it a manifestation of having atherosclerotic disease,” said Dr. J. Travis Wilson, cardiologist with Allegheny Health Network and Canonsburg Hospital. “I would submit that probably those patients who get less sleep, worse quality of sleep, that serves as a marker of various risk factors for you to develop atherosclerotic disease.”

The study took into account known risk factors such as diabetes, smoking and high blood pressure. Still, in those groups that got less sleep and worse quality of sleep, there was an increased prevalence of smoking, obesity and high blood pressure, which are all markers for the development of atherosclerotic disease. They also tended to drink more alcohol than those who got more or better quality sleep. Wilson said the results do provide some interesting new information.

“This is a test that doesn’t involve any radiation, is non-invasive and serves as a marker for identifying those patients who are at risk to develop atherosclerotic disease,” Wilson said.

He said he can see this research translating into doctors routinely asking about sleep hygiene.

“If you’re that person who feels that you don’t get enough sleep, or that your quality of sleep is not good, then that leads to a conversation about your risk factors for developing atherosclerotic disease,” he said. “It may help us and guide us as physicians to be more aggressive with modifying your risk.”

Wilson added the study’s results could also mean that lack of sleep does directly increase your risk independent of other factors.

“That gives us guidance as physicians that we need to address sleep hygiene and make it part of our routine questions that go hand in hand with smoking and physical activity and diet,” he said. “If we feel that your sleep hygiene is not optimal, then to make that recommendation, what can you do in your life to increase the duration of sleep or improve your quality of sleep?”

Most people would love to sleep more and have better quality sleep, but it’s not always possible.

“We’ve known for years that people who get too much sleep, and people who don’t get enough sleep tend to have worse health outcomes,” said Dr. Euhan J. Lee, pulmonologist with Allegheny Health Network Sleep Medicine at Canonsburg Hospital. “And we never really knew why. These population-based studies only show association, not necessarily a causation. I think this study is nice because it actually shows there’s physiologic, anatomic changes that are correlated with sleep duration. And I think that hasn’t really been shown before.”

He cautioned, however, that is still doesn’t show a causation.

“There’s still a thought that it could be identifying people who already have problems, who just sleep worse because they have health problems or vice versa. It may be both,” he said.

Lee said sleep is vital for every organism on the planet – even cells and viruses have some type of rest period. Sleep studies have shown that humans who are sleep-deprived in the short term can develop health problems, psychosis and even die. Sleep plays a crucial role in our immune system and brain functions such a memory and concentration as well as metabolism.

The question is how much sleep do we need?

“We’re not really sure why one individual might need more and one individual might need less,” Lee said. “Those things are still being looked at from an individual standpoint. I think it’s very clear that most people don’t get enough sleep. As a population, we’re all sleep-deprived.”

Conventional wisdom shows that we need eight hours of sleep per night. Yet the most recent data shows the general American population sleeps less than six hours a night.

“That’s a pretty significant, chronic sleep deprivation,” Lee said. “Some individuals need more or less. I’ve had patients who need four or five hours of sleep. They feel fine, they don’t drink caffeine, they function well. Then I have patients who need 15 to 16 hours of sleep at night.

It demonstrates there is no normal when it comes to sleep patterns and Lee said sleep deprivation is largely our own fault.

“Most of us don’t go to bed early enough,” he said. “Most of us wake up earlier than we’d like to, we all keep busy with work and family, or what have you. It’s now a 24/7 world and it makes it so sleep is harder and harder to come by.”

To get more and better quality sleep, Lee recommended being goal-oriented. Shift sleep times and patterns gradually over seveal weeks to add more time.

“Giving yourself a little bit more defined goals is more helpful than just the generic goal to sleep better,” he said.