Sleep quality may deliver key health benefits

Getting enough sleep each night is important. But an American Heart Association scientific statement suggests that sleep quality may be just as important to overall health as sleep duration.

Growing evidence links multiple components of sleep to heart and cardiometabolic health, according to the report. Poor sleep has been linked to increased body fat, elevated blood sugar, unhealthy cholesterol and higher blood pressure. Researchers note that restorative sleep supports both physical health and mental well-being.

“There is increasing evidence that sleep health is about more than the number of hours you sleep each night,” said Marie-Pierre St-Onge, chair of the writing group and director of the Center of Excellence for Sleep & Circadian Research at Columbia University Irving Medical Center.

"Suboptimal sleep raises the risk for cardiovascular disease, along with risk of cognitive decline, depression, obesity, as well as high blood pressure, blood sugar and cholesterol levels,” she said.

The Heart Association recommends a nightly sleep duration of 7 to 9 hours for most adults. Studies show that too little sleep increases the risk of atrial fibrillation, a type of irregular heartbeat; cardiometabolic syndrome, a group of conditions that raise the risk for Type 2 diabetes, heart disease and stroke; and blood pressure that doesn’t decrease as much as it should. Getting too much sleep has also been linked to a higher risk for cardiometabolic syndrome, along with stiffened arteries, stroke or death from heart disease or stroke.

Components of healthy sleep

However, sleep duration is just one aspect of a good night’s rest. According to the report, no single component captures the full sleep experience or the body's response. Other key factors of healthy sleep include:;

Continuity measures time to fall asleep; number of awakenings and unplanned early awakenings. Poor sleep continuity has been linked to a higher risk for AFib, heart attack, high blood pressure and greater insulin resistance.

Timing refers to when a person typically goes to sleep and whether sleep occurs during the day or night. Some studies suggest going to sleep at midnight or later may raise the risk of being diagnosed as overweight or obese, insulin resistance and high blood pressure.

Satisfaction is a person’s reported perception of their sleep experience.

Regularity of sleep patterns is the consistency of timing and duration of sleep.

Daytime functioning, or how alert a person feels during the day, also affects heart health. Excessive daytime sleepiness has been linked to heart disease and stroke and related deaths.

Sleep architecture, or the cycling between stages of light and deep sleep, may also play a role in heart health. Some studies suggest that sleep disruptions affect people differently depending on the cycle disrupted.

Factors affecting sleep quality

Social drivers of health, such as socioeconomic status, pollution and safety, impact sleep, according to the statement. More than 300 studies show consistent links between lower socioeconomic status and suboptimal sleep health. Research has shown that people in historically underrepresented racial and ethnic groups sleep less and are more likely to experience worse sleep continuity and sleep satisfaction, later bedtimes, more irregular sleep patterns, higher daytime drowsiness and a greater number of sleep disorders.

“It’s important to know that every individual has different sleep experiences, and these differences may contribute to other health inequities,” St-Onge said. “Including different components of sleep in discussions with patients provides essential information that can help health care professionals improve care.”

The statement concludes that advances are needed in how to measure and analyze the full range of sleep components affecting health, so they can be better addressed and improved.
St-Onge said people should pay close attention to how they sleep, just as they do to other aspects of health and well-being.

“Some changes in sleep across the life course are natural,” she said. “However, individuals should not accept poor or worsening sleep as a ‘fact of life’ or unavoidable consequence of the aging process.”