Sleep disorders – including too little or too much sleep – may contribute to heart disease risk factors, the American Heart Association said in its first statement on the risks of sleep problems.
Focus on insomnia
But, the heart group stopped short of recommending a certain amount of sleep per night.
"We know that short sleep, usually defined as under seven hours per night, overly long sleep, usually defined as more than nine hours per night, and sleep disorders may increase some cardiovascular risk factors, but we don't know if improving sleep quality reduces those risk factors," Marie-Pierre St-Onge said in a news release from the heart association. St-Onge is an associate professor of nutritional medicine at Columbia University in New York City.
At the request of the heart association, St-Onge and her colleagues reviewed research into sleep and heart health.
Read: Your sleeping habits may affect your heart
Much of the research focuses on insomnia. Insomnia is defined as having trouble falling or staying asleep for at least three days a week for three or more months. Another focus of the research has been sleep apnoea. That's a condition that causes a person's breathing to stop momentarily an average of five or more times per hour of sleep.
Additional research needed
Research has also linked sleep problems to obesity and type 2 diabetes, St-Onge said.
"Those are the two main conditions in which there are intervention studies that show that risk factors are increased when sleep is altered," St-Onge said. But more research is needed to better understand the connections, she added.
Also, more research is needed to provide better insight into whether sleep troubles affect cholesterol, triglycerides and signs of inflammation, St-Onge said.
Read: Too much, too little sleep linked to heart woes
Finally, she added, additional research is needed to determine whether poor sleep plays a causal role in type 2 diabetes, high blood pressure, and heart disease and stroke. Research so far hasn't shown a direct link.
St-Onge recommended that medical providers ask patients about the length of their sleep and whether they snore.
A balanced diet
Patients who are overweight and snore should see a sleep specialist, she suggested, and those with general sleep problems should be told how to improve sleep and be tracked over time.
"Patients need to be aware that adequate sleep is important, just as being physically active and eating a balanced diet rich in fruits, vegetables, whole grains, lean meat and fish are important for cardiovascular health," she said.
Read: Too little sleep linked to heart disease risk
"Sleep is another type of ammunition that we can tailor to improve health," St-Onge suggested.
According to the US National Heart, Lung, and Blood Institute, about 50 million to 70 million adults in the United States have a sleep disorder or don't get enough sleep on a regular basis.
In 2009, about 29 percent of Americans got less than seven hours of sleep nightly. In 1977, that number was 22 percent, the researchers said.
The American Heart Association statement was published in the journal Circulation.