Getting too little—or too much—sleep may be bad for your heart

Whether you like to burn the midnight oil to check emails or binge-watch your favorite series, toss and turn or sleep until mid-morning, it seems the amount of sleep you get matters when it comes to your future vascular and heart health.

In a new study, researchers found that compared with people who slept for longer or shorter periods of time, those who reported sleeping seven or eight hours a night had much less evidence of stiffness in their arteries.

This indicates a lower chance of developing heart disease or suffering a stroke.

The researchers assessed sleep patterns in 1,752 people living in the Corinthia region of Greece using a standard questionnaire that was fielded by a trained cardiologist, primary care provider or nurse.

Participants were then divided into one of four groups based on self-reported sleep duration: normal (seven to eight hours a night), short sleep duration (six to seven hours a night), very short sleep duration (less than six hours a night) or long sleep duration (greater than eight hours a night).

Participants represented a broad spectrum of the general public, including healthy people as well as those with cardiovascular risk factors and established heart disease, and most were from rural areas with less than 1,000-2,000 inhabitants.

They ranged in age from 40 to 98 years, with a mean age of 64 years old.

At the time of the study, each participant also underwent ultrasound imaging to measure the thickness of the inner part of the arterial wall.

The thickening of the arterial walls reflects plaque buildup and is associated with an increased risk of stroke and other cardiovascular events.

Even after accounting for other known risk factors for heart disease or stroke, the team found people who slept less than six hours or more than eight hours a night had much greater odds of having plaque buildup in the walls of their carotid arteries—a 54% and 39% increase, respectively—compared with those who got seven or eight hours of shut-eye.

The study adds to mounting evidence that sleep patterns, similar to diet and exercise, may play a defining role in someone’s heart risk.

The study uncovers a U-shaped pattern between sleep duration and early indicators of atherosclerosis, which underscores the need for a balanced sleep pattern.

Plaque build-up in the artery walls was greater in both the shorter and longer sleep duration groups as compared to normal sleep duration.

Currently, scientists don’t fully understand the relationship between sleep and cardiovascular health.

It could be that sympathetic nervous system withdrawal or a slowing [of this system] that occurs during sleep may act as a recovery phase for [usual] vascular and cardiac strain.

Moreover, short sleep duration may be associated with increased cardiovascular risk factors—for example, unhealthy diet, stress, being overweight or greater alcohol consumption—whereas longer sleep duration may be associated with a less active lifestyle pattern and lower physical activity.

The team says the message, based on these findings, is ‘sleep well, but not too well.’ Getting too little sleep appears bad for your health but too much seems to be harmful as well.

The lead author of the study is Evangelos Oikonomou, MD, a consultant cardiologist.

The study was presented at the American College of Cardiology’s Annual Scientific Session Together with the World Congress of Cardiology.

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