Beijing, Apr 1 (IANS): Individuals who find it hard to fall asleep must wake up to the health problems that poor sleep poses. Researchers have found that suffering from insomnia may put people at increased risk of heart attack and stroke.

Women with insomnia symptoms may have a slightly higher risk of cardiovascular and stroke events than men, according to the study published in the European Journal of Preventive Cardiology.

"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 the study's first author Qiao He from China Medical University in Shenyang, China.

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

To find out, the authors analysed 15 prospective cohort studies with a total of 160, 867 participants.

The current analysis assessed the association between insomnia symptoms and incidence of death from cardiovascular disease (acute myocardial infarction, coronary heart disease, heart failure), stroke, or a combination of events.

Insomnia symptoms included difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening, and non-restorative sleep.

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

The underlying mechanisms for these links are not completely understood, she added.

"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," she explained.