Insomniacs have a couple of more things to worry about as they lie sleepless staring at the ceiling — insomnia increases the risk of heart attack and stroke.

"Sleep is important for biological recovery and takes around a third of our lifetime, but in modern society more and more people complain of insomnia," said Qiao He, first author of a Chinese study that showed the cardiovascular risk of sleepless nights.

Insomnia is a widespread problem in the United States. According to Consumer Reports, more than a quarter of American adults say they have trouble either going to sleep or staying asleep most nights, and 68 percent of adults have problems sleeping at least once a week.

"Researchers have found associations between insomnia and poor health outcomes," continued He. "But the links between insomnia and heart disease or stroke have been inconsistent."

For the current study, which was published in the European Journal of Preventive Cardiology, researchers analyzed 15 studies involving a total of 160, 867 participants. Follow-up times varied from three to almost 30 years.

They found significant associations between difficulty initiating sleep, difficulty maintaining sleep, and non-restorative sleep and the risk of heart disease and stroke when compared to those who didn't have insomnia.

"We found that difficulty initiating sleep, difficulty maintaining sleep, or non-restorative sleep were associated with 27 percent, 11 percent, and 18 percent higher risks of cardiovascular and stroke events, respectively."

He noted that the underlying mechanisms for the links aren't completely understood. "Previous studies have shown that insomnia may change metabolism and endocrine function, increase sympathetic activation, raise blood pressure, and elevate levels of proinflammatory and inflammatory cytokines — all of which are risk factors for cardiovascular disease and stroke."

Many sufferers of insomnia resort to sleeping pills, but they come with a long list of side effects. If you have insomnia, try these tips for a restful night's sleep:

• Be consistent. Go to bed and get up at the same time, even on weekends.

• Keep your room dark. Eliminate even night lights and bright clock dials.

• Keep your bedroom cool.

• Don’t take naps during the day, especially after 3:00 p.m.

• Exercise regularly – but early in the day – and avoid exercising at night.

• Don’t eat large meals close to bedtime.