Length of sleep linked to risk of heart disease

Sleep irregularities may be tied to a variety of health problems, such as diabetes and obesity, that can increase the risk of cardiovascular disease, a leading US doctors group says.

The risk may go up when people get too little sleep, or too much, according to a statement from the American Heart Association (AHA).

“We do not know the optimal amount of sleep needed to minimize the risk of heart disease,” but people who get less than seven hours a night or more than nine hours may be more at risk than their peers who fall somewhere in the middle of that range, said lead statement author Dr. Marie St-Onge of Columbia University in New York City, in an email.

Previous research suggests that sleep irregularities can increase people’s risks for a variety of cardiovascular disorders, such as clogged or hardened arteries, high blood pressure, irregular heartbeat, and stroke, as well as metabolic problems such as high cholesterol, obesity and diabetes that all contribute to cardiovascular disease.

There is certainly a vicious cycle that may be going on with sleep and chronic diseases,” St-Onge added. “Bad sleep can increase the risk of obesity which then increases the risk of sleep disorders.”

Much of the scientific research about sleep and heart health focuses on insomnia or sleep apnea.

People are diagnosed with insomnia when they have difficulty falling or staying asleep for at least three nights a week for three or more months.

Sleep apnea is diagnosed when someone has an average of five or more pauses in breathing, which can last seconds to minutes, per hour of sleep. These pauses are most commonly due to a narrowed airway.

Often, these sleep issues are tied to two other health problems: diabetes and obesity. Some studies have found sleep can influence what people eat and impact their risk of obesity, for example.

But more research is needed to see how sleep influences weight over long periods of time, according to the AHA statement.

Longer studies might also help explain how sleep variations influence cholesterol levels, diabetes, blood pressure or other risk factors for cardiovascular disease.

It’s also unclear whether treating sleep disorders could lower the risk of cardiovascular disease.

The problem is that chronic diseases, like cardiovascular disease, develop gradually,” said Kristen Knutson, a researcher at the University of Chicago who wasn’t involved in the AHA statement.