One of the underrated advantages of youth is the ability to sleep undisturbed through the night. In my early 20s, for example, I once slept through a minor early-morning earthquake in central Greece. Even into my late 30s and early 40s, my nocturnal obliviousness often insulated me from late-night infant squalls — much to My Lovely Wife’s dismay.
Nowadays, however, it’s the rare morning that I awaken without having navigated a trip or two to the bathroom during the night. And most U.S. seniors will tell you they can only dream of experiencing the blissful slumber they enjoyed in their younger years. By some estimates, about half of the Medicare set regularly struggles to sleep uninterruptedly for the recommended seven to nine hours a night.
We can lay the blame for our sleepless nights on any number of age-related sources: hormonal disruptions, the side effects of prescription drugs, chronic pain, sleep apnea, restless legs syndrome. And there’s plenty of evidence to suggest poor sleep patterns can increase the risk of developing high blood pressure, cardiovascular disease, and type 2 diabetes. Chronic insomnia, new research suggests, may even accelerate the aging process in the brain.
Diego Carvalho, MD, and his team of researchers earlier this month released the results of a study showing the cognitive effects of sleeplessness among 2,750 older participants in the Mayo Clinic Study of Aging. After reviewing sleep patterns and cognitive assessments over a five-year period, they concluded that the brains of insomnia sufferers aged at a more rapid rate — the equivalent of 3.5 years — than those who slept more soundly. Not surprisingly, they were also 40 percent more likely to develop dementia.
“We found an association between insomnia, cognitive decline, and increased risk for cognitive impairment,” Carvalho, a sleep-medicine specialist at the Mayo Clinic, writes in the journal Neurology. “Insomnia with reduced sleep was associated with worse cognitive performance and poorer brain health at baseline.”
The neurological effects of poor sleep patterns are fairly well established. Inadequate shuteye can impede communication between nerve cells, reduce the brain’s ability to remove the toxins that accumulate during your waking hours, and erode the pathways required for creating new memories.
Sleep apnea can produce particularly damaging effects, according to a recent study out of the University of California, Irvine. By repeatedly causing a person to awaken during the night to catch their breath, the condition can lead to lower oxygen levels, damaging blood flow in the brain. This is especially true during periods of REM sleep, Bryce Mander, PhD, and his team learned.
The damage, measured by the presence of white matter observed during brain scans, primarily appeared in parts of the brain associated with memory. Study participants whose blood-oxygen saturation levels dipped below 90 percent most frequently during their REM sleep cycles displayed less volume in the hippocampus and reduced thickness in the entorhinal cortex — both of which explain their subpar performance on memory tests, Mander concludes.
“Obstructive sleep apnea is a sleep disorder that increases with age, and low oxygen levels during sleep can harm the ability of our brain and body to function properly,” he explains. “Our study found that low oxygen levels from obstructive sleep apnea, especially during REM sleep, may be linked to cognitive decline due to damage to the small blood vessels in the brain and the downstream impact of this damage on parts of the brain associated with memory.”
As disturbing as these conclusions appear, however, neither study can claim to show that sleeplessness causes cognitive dysfunction; rather, they show only that there’s a connection. Mander’s study, it should be noted, involved a mere 37 participants; and, as Carvalho tells The Washington Post, much more research will be needed to determine a conclusive link. “It could also be that poor sleep early on can be an indicator of cognitive decline,” he admits. “It’s very hard to untangle.”
While we wait for more evidence to accumulate, it’s helpful to review the time-honored tips for a good night’s sleep: maintaining a regular bedtime ritual and schedule, avoiding midday naps and late-evening screens, skipping caffeine and alcohol before bed, and getting some exercise.
And as the scientific community continues to churn out these sorts of reports, I might also suggest that we remind ourselves that the vast majority of research tends to be preliminary. Let’s not lose any sleep over it.
