Tossing and turning at night instead of getting some much-needed, un-interrupted sleep can cause more than just a bad case of bedhead and a grumpy disposition the following morning. Recent studies link insomnia to an elevated risk of heart attack and stroke.
An estimated 10 percent of Americans are living with chronic insomnia disorder, where people report being unable to sleep at least three nights per week for at least three months. Past studies attempting to link insomnia and cardiovascular problems have put forth inconsistent results, but a new study published in the European Journal of Preventative Cardiology outlines some definitive findings.
A team of researchers conducted a meta-analysis, including 15 total studies and over 160,000 participants. Scientists conducting the study looked for evidence of an association between insomnia symptoms (difficulty initiating sleep, difficulty maintaining sleep, early-morning awakening, non-restorative sleep) and incidence of or death from cardiovascular disease (acute myocardial infarction, coronary heart disease, heart failure, stroke, or a combination of any of these).
Study researchers followed up with their participants after an average of about thirty years, and more than eleven thousand adverse health events had occurred in the study participants during this time.
"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 first author of the study, Qiao He, a Master's degree student at China Medical University, Shenyang, China. "We found that difficulty initiating sleep, difficulty maintaining sleep, or non-restorative sleep were associated with 27%, 11%, and 18% higher risks of cardiovascular and stroke events, respectively.”
The specific path connecting insomnia symptoms and adverse health events is still blurry, but researchers involved in the meta-analysis believe that metabolism changes, endocrine dysfunction, increased blood pressure, and elevated levels of proinflammatory cytokines are all involved. More studies will have to be completed in order to understand the complete relationship between insomnia and cardiovascular disease, but a link is definitely there.