Study Says Sleeping This Much May Help Evade Heart Disease

Researchers claim to have found the “sweet spot” for perfect sleep time and warn that deviating from it too much can be fatal.

The report comes out of the Onassis Cardiac Surgery Center in Athens, Greece, where lead researcher Dr. Epameinondas Fountas and his team endeavored to establish a connection between sleep duration and rates of cardiovascular disease. To do this, they used a meta-analysis, which allowed them to aggregate results from 11 prospective studies on the subject.

Researchers then divided the sample size of over 1 million adults into three groups: one who slept less than 6 hours a night, one that slept more than 8 hours, and a “control” group that got between 6-8 hours of shut-eye. What they discovered was that those who either slept less than six hours or more than eight had a greater risk of developing or dying from coronary artery disease or stroke.

As Dr. Fountas explained to me, sleep duration is only one out of many sleep quality indices, including continuity, depth, and distribution throughout the day. As with any of these factors, sleep duration has a “normal value,” which research has shown to be between six and eight hours. Once we go above or below that normal value, our body is then forced to use homeostasis, described by Fountas as “a sum of actions to preserve proper function of biological systems.” In his words:

So, when we sleep more than eight or less than six hours… we either overuse homeostasis (which means abnormal condition for our bodies) or the homeostasis functionality is broken. [This translates to] more oxygen free roots circulating in our vessels, a higher calorie uptake, [as well as] increased blood pressure and inflammation.

Note: The content on Sleepopolis is meant to be informative in nature, but shouldn’t be taken as medical advice or take the place of medical advice from a trained professional. Consult with a qualified medical provider before modifying your child’s existing sleep routine. If you feel you or your baby may be suffering from any sleep disorder or medical condition, please see a healthcare provider. 

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While intriguing, Dr. Fountas stressed that the findings are not conclusive and that more research needs to be done to understand the effects of sleep duration on heart health.

“Research must focus on how long sleep duration is biologically related to cardiovascular disease,” he said. “Furthermore, other sleep quality indices have to be investigated about how they affect the incidence of cardiovascular disease, specifically combined with sleep duration. This year I plan to make a study on these factors.”


According to the National Sleep Foundation, restorative sleep is vital to heart health. As the organization writes on its website: “Without long, deep periods of rest, certain chemicals are activated that keep the body from achieving extended periods in which heart rate and blood pressure are lowered. Over time, this can lead to higher blood pressure during the day and a greater chance of cardiovascular problems.”

This sentiment has been echoed in a surge of recent research on the topic. Aside from this meta-analysis, a recent study found that clocking in less than five hours of sleep a night could double a person’s risk of developing heart disease and another suggested that poor sleep could negatively effect the cardiovascular health of kids.

Facing such bleak findings, one may wonder: Is it possible to reverse the damage and improve the hygiene of one’s heart? For Dr. Fountas, who sought to study the relationship because of his own personal struggle to achieve optimal sleep, the answer is likely yes.

“Abolish sentimental stress and reduce workload when possible,” he recommended. “Think of sleep as you think of other biological needs, like nutrition. You want it to be of high quality and you spend a lot of time thinking about that. Organize your sleep in order to be continuous and deep. An expert’s consultation (psychiatrist) for severe sleep disorders is appropriate in some cases.”

Cody Gohl

Cody is a former staff editor at Sleepopolis. His work has appeared online for Esquire, Next, LOGO TV, Fandom, Citylife, The Manual, and more.

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