Okay, not just one night, but persistent insomnia – constant waking in the middle of the night and difficulty falling asleep – can have life-threatening – and too often unexpected – effects. The news reflects the findings of teams of researchers across the country, many of them publishing their studies at June’s Sleep 2012 Conference in Boston.
Insomnia – the inability to fall asleep or remain asleep – may increase the likelihood of developing hypertension.
“The cause of hypertension in insomniacs is due to the number of times the individual wakes during the night as well as their sleep latency — the length of time it takes to accomplish the transition from full wakefulness to sleep,” reports Christopher Drake, associate scientist at the Henry Ford Hospital Sleep Disorders and Research Center (Detroit) and lead author of the study.
Thirty to forty percent of American adults say they have some symptoms of insomnia in a given year, according to the National Center for Sleep Disorders Research at the National Institutes of Health. About 10 to 15 percent of adults say they have chronic insomnia.
The researchers at the Henry Ford Hospital Sleep Disorders and Research Center compared 5314 subjects Internet-based questionnaires on insomnia symptoms, presence and severity of hypertension and sleep health habits. “We found that the longer it took the subjects to fall asleep and more times they woke during the night, the more severe their hypertension,” reported Drake. Normal sleepers were compared to insomniacs for the prevalence of hypertension.
In another study – of 5,666 working adults aged 45 older and all free from strokes and stroke symptoms, transient ischemic attack, or sleep-disordered breathing problems who were followed over a three-year period – researchers found that middle- to older-aged subjects who regularly get fewer than six hours of sleep a night have an increased stroke risk, even if they don’t have a history of stroke, aren’t overweight and don’t have an increased risk for sleep apnea. Importantly, the researchers found a link between getting fewer than six hours of sleep a night and strokes is strong among normal weight subjects but did not find the same link in overweight and obese study participants.
It is possible that short sleep affects stroke risks by acting on other, known risk factors: increasing blood pressure, spurring inflammation and altering metabolic hormones. Even after adjusting for sleep apnea, a known risk factor for strokes, the researchers found that a nightly sleep of less than six hours was strongly associated with a greater incidence of stroke.
Their findings are especially important because it is estimated that 30 percent of working adults get fewer than six hours of sleep each night. “We speculate that short sleep duration is a precursor to other traditional stroke risk factors, and once these traditional stroke risk factors are present, then perhaps they become stronger risk factors than sleep duration alone,” reported researcher Megan Ruiter of the University of Alabama at Birmingham. “A lot of people say that when things get stressful and schedules get tight sleep is the first thing to get sacrificed. It turns out that it’s a lot more problematic than we previously realized.”
“These people sleeping less than six hours had a four times increased risk of experiencing these stroke symptoms compared to their normal weight counterparts that were getting seven to eight hours,” note Ruiter.
In a new report at the 2012 American Stroke Association’s International Stroke Conference, researchers noted that individuals with sleep apnea may have an increased risk of so-called “silent strokes” and small lesions in the brain. “We found a surprisingly high frequency of sleep apnea in patients with stroke that underlies its clinical relevance as a stroke risk factor,” noted Jessica Kepplinger, M.D., stroke fellow in the University Stroke Center’s Department of Neurology at the University of Technology (Dresden, Germany).
“Sleep apnea is widely unrecognized and still neglected,” noted Kepplinger. “Patients who had severe sleep apnea were more likely to have silent strokes and the severity of sleep apnea increased the risk of being disabled at hospital discharge.”
The researchers report that 91 percent of patients studied – 51 of 56 – who had a stroke had sleep apnea and were more likely to have silent strokes and white matter lesions in the brain that increased the risk of disability at the time of their discharge; having more than five sleep apnea episodes per night was associated with silent strokes; more than one-third of patients with white matter lesions had severe sleep apnea and more than 50 percent of silent stroke patients had sleep apnea; correlations between sleep apnea and silent strokes were thje same for men and women.
“We have been extremely successful in helping our clients improve their sleep!” reports Dr. Flynn, PsyD, the psychological director at The Brain Training Centers of Florida.