We spend a third of our lives sleeping, not counting naps. Resting has its function, as it gives the brain time to recover from daily wear and tear. To this we must add processes such as the consolidation of certain types of memories, the elimination of brain toxins or neuronal regeneration. In recent days, two studies have provided new evidence that associates factors that sabotage our sleep and other bedtime habits with an increased risk of suffering from cognitive impairment, Alzheimer’s or stroke. Specifically, taking naps that are too long or suffering from sleep apnea.
On the one hand, a work published in the journal Neurologyfrom the American Academy of Neurology, establishes an association between sleep problems such as apnea, snoring, and sleeping too much or too little with an increased chance of suffering a stroke. The results concluded that those who slept less than five hours a day on average were three times more likely to have a stroke than those who slept seven.
Long naps of more than an hour and unplanned ones were also related to strokes. Those who slept this way had an 88% higher risk of stroke than people who did not. In the case of snoring, the risk increased to 91%. But one of the most dangerous factors proved to be sleep apnea, a disorder that tripled the risk of stroke. In this work, led by Christine McCarthy, a researcher at the University of Galway (Ireland), 4,496 people participated. Half of them had suffered a stroke.
On the other hand, a small but significant study published in the specialized magazine Frontiers in Sleep suggests that having apnea may be enough for a declining brain health among middle-aged men, even if they are healthy and have no other major health problems. Specifically, this deterioration can manifest itself as “a significant memory lossan alteration of spatial reasoning and/or inability to concentrate and think clearly”. For all these reasons, the research opens the door to link apnea with Alzheimer’s.
For the study, the mental status of 27 male patients with apnea and 7 men without it, who had no other medical problems, and were between the ages of 35 and 70, were followed. None smoked or drank and none was obese. They were given a battery of thought processing tests that they described as “very sensitive.” The result? “Patients with mild or severe sleep apnea fared significantly worse”.
Specifically, they failed tests of short-term visual memory, the ability to plan and make decisions, or the ability to “read” emotions and social situations. AND the more severe the sleep apnea, the worse outcomes they got, according to the report.
In addition, Dr. Ivana Rosenzweig, author of the study and director of the Center for Sleep and Brain Plasticity at King’s College London (United Kingdom) points out that between 15% and 30% of men suffer from sleep apnea. Among women, the proportion drops to 10% and 15%. However, the scientist observed that this difference occurs more among premenopausal women and, after menopause, that gender difference evaporates.
Reactions and criticism
With respect to the first study, the author of the paper herself highlights the importance of her findings, but she is also cautious when it comes to establishing a cause-effect relationship between sleeping too little or too much with a stroke. In this sense, she pointed out that little sleep “may be associated with other risk factors, such as high blood pressure, for example” or “It can also be a sign that there is another disease unknown”.
For his part, Rosenzweig stressed that his research is a small “proof of concept” study, so cause and effect cannot yet be exactly established. Still, the “study suggests that obstructive sleep apnea itself is enough to cause a change in thinking ability” And he added: “Of course, this will have to be demonstrated in much larger studies that follow patients over a longer period of time.”
Dr. Andrew Varga, a sleep medicine physician at the Mount Sinai Comprehensive Sleep Center in New York who has spent his entire career examining A possible connection between grief and Alzheimer’s, agreed with the study results in statements to HealthDay. For him, the idea that the two are related “makes sense.”
According to the expert, this is because all organs, including the brain, need oxygen to function, and one of the main characteristics of sleep apnea “is intermittent hypoxia, that is, the repeated decrease in oxygen levels in the blood.” Still, it indicates that larger studies including a follow-up evaluation will be required. “The only thing that can be said is that sleep apnea seems to lead to worse outcomes in these types of tests,” he said. He concluded: “I think sleep apnea is a risk factor. But it’s a pretty big leap to draw that conclusion from this paper.”