Are you feeling sleepy all the time, be it due to not enough sleep at night or simply because you feel tired? If you answered with a “yes”, and you’re that person who has to take multiple naps just to get through the day or someone who chronically doesn’t get enough sleep, you’d better pay attention to this research. In a fresh 2019 study, neuroscientists from University of California San Francisco (UCSF) have linked excessive napping to a dangerous disease that seems to be on everyone’s mind nowadays, Alzheimer’s (pun not intended).
And while this recent study sheds light on what could be the cause of increased sleepiness in patients with Alzheimer’s, the idea of sleep disorders and Alzheimer’s being somehow linked isn’t new, as previous research, too, has confirmed that poor sleep, particularly a shortage of sleep, is more common in Alzheimer’s patients than other populations.
As you may know, Alzheimer’s is a progressive disease that interferes with a person’s memory and thinking skills, gradually degrading the brain tissue and making the neural connections weaker and weaker. The disease was observed to affect the outermost layer of the brain, the cortex, which is where all the neuronal nuclei that are responsible for cognition, memory, and thinking reside, but the UCSF study aimed to look at 2 very different areas associated with sleep regulation: the brainstem and some subcortical regions.
Having compared post-mortem samples of 13 Alzheimer’s patients to those of control subjects, the researchers found that the brain areas associated with wakefulness were severely affected in Alzheimer’s patients. More specifically, the researchers found tau protein buildup tangles in the conducting fibers of neurons, which cut off the nutrient supply to the neuron cell bodies and brought about the death of the nerve cells in the studied regions.
Tau proteins normally help nutrient supply, but for reasons unknown, this protein bunched up in tangles in Alzheimer’s patients. These and other protein tangles are the hallmarks of Alzheimer’s, but this was the first time they were found in brain regions other than the cortex, confirming that Alzheimer’s disease is devastating to the entire brain.
The evidence from this study further extends previous conclusions regarding the effects of sleep deprivation on the development of Alzheimer’s. Namely, observational studies suggested that a lack of sleep increase one’s risk of developing Alzheimer’s while microbiological explorations linked poor sleep to an increased risk of amyloid plaques in the brain. Amyloids are other proteins also widely associated with Alzheimer’s disease risk.
The obvious limitation of all of these studies is that common to all correlational research: we don’t know if it’s the lack of sleep that contributed to Alzheimer’s or the other way around. Still, it’s just another reason to get enough sleep every night, just in case, and more than enough proof to take our sleep more seriously and realize that, sometimes, feeling sleepy or sleepless all the time is more than enough reason to see the doc.