(NBC NEWS) — People who have trouble sleeping may be at a higher risk for developing serious health issues.
Chinese researchers followed more than 487,000 people for an average of 10 years and all had no history of heart disease or stroke.
Those who exhibited at least one symptom of insomnia a couple times a week were more likely to have a stroke or heart attack.
The link was strongest in younger people and in those who did not have high blood pressure at the start of the study.
The scientists say the study did not show cause and effect, only that there was an association between the two.
The symptoms of insomnia include having trouble falling asleep or staying asleep, waking up too early, or trouble staying focused during the day due to poor sleep.