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Could Poor Sleep Lead to Alzheimer's Disease?

I don’t get enough sleep.

It’s a simple statement but one that I know is true for not only me but for millions of others. The problem is that sleep is about a lot more than just rest, and not getting enough sleep can cause a host of problems from fatigue, to memory issues, and even long term illness. But, sleep deprivation may cause even bigger issues.

There are four stage of sleep, with the third being the deep sleep that provides Delta waves to help the mind and body heal, and the fourth stage is REM sleep which allows our brain to organize information, improving learning and memory. Once you understand the purpose of Delta waves and REM sleep, it’s understandable that REM sleep occurs at the highest levels in babies because they are learning the most. But, even aging adults need these deep stages of sleep, especially the Delta waves that help the body heal.

The problem is that not getting these stages does more harm that just decreasing our ability to heal and remember. According to researcher Adam Spira, not getting enough sleep may even lead to Alzheimer’s disease. His study at John’s Hopkins showed a definite link between sleep deprivation and the amyloid plaques commonly associated with Alzheimer’s disease.

Unfortunately, the study doesn’t tell us if the plaque causes the poor sleep or if the poor sleep causes the plaque.

Even without knowing the cause and effect relationship between the plaque and poor sleep, it seems pretty simple to connect the dots. We know that Delta waves help heal the body, and we know that REM sleep helps to improve memory and learning. Alzheimer’s is associated with memory issues, and physically can only be diagnosed after death when the brain is autopsied, revealing specific plaques and tangles.

Of course, it’s possible that the plaques and tangles already existed and they are the reason that a person with Alzheimer’s disease has poor sleep, and the poor sleep over time leads to memory issues. However, it does seem that as Alzheimer’s progresses so do the sleep issues. After all, it is the nighttime waking that often leads to these patients being institutionalized, because their care-givers cannot be awake 24/7 to keep an eye on them.

Whether sleep issues cause Alzheimer’s or Alzheimer’s causes the sleep disturbances, the decreased sleep certainly can’t help the symptoms of memory loss and disorientation associated with Alzheimer’s. These symptoms are common in sleep deprivation at any age, even in healthy individuals.

So, how is it possible that lack of sleep could lead to Alzheimer’s disease?

When you look at what sleep does for our bodies, it’s pretty clear. Not only does sleep help aid our body’s healing processes and encourage learning and memory, but sleep also helps clear our bodies of toxins that accumulate during the day – including amyloid proteins. Not sleeping means that the amyloid proteins don’t get cleared, and this build-up eventually leads to the plaques associated with Alzheimer’s, beginning the degenerative chain of events that eventually leads to neuronal death.

This build-up of amyloid proteins is seen years before other Alzheimer’s symptoms and may well be an early symptom of the disease. So is it possible that improving sleep early on may help prevent this plaque aggregation and therefore prevent Alzheimer’s?

The answer seems to be yes.

Studies have indicated that sleep deprivation leads to amyloid plaque deposits within just three weeks. This seems to create a cyclical issue where the plaques decrease sleep over time, which creates an increase in plaque deposits. The key seems to be in increasing quality sleep early on before it becomes an issue.

But, how do we do this?

The first key is in recognizing that there is an issue. I know that personally I’ve been guilty at times of ignoring my own sleep issues, thinking that I’m just stressed out and that it will eventually improve on its own. And I know that I’m not alone. The problem is that it usually doesn’t get better without making some changes.

A 2015 review by Sharma and colleagues suggested two potential focus areas – melatonin and serotonin.

Melatonin is metabolite synthesized in the pineal gland that not only aids in the controlling the circadian rhythm but also in clearing the body of toxins and improving immune function. Sleep deprivation also increases serotonin levels, which normally decrease during deep and REM sleep. This increase in serotonin may result in the decreased melatonin. Because Alzheimer’s patients have been shown to have decreased melatonin levels, medications that reduce serotonin levels may be helpful in improving sleep patterns (as may melatonin supplementation).

Unfortunately, the relationship between sleep and Alzheimer’s is still a bit of a “chicken-and-egg” problem. While adjusting melatonin and serotonin may help sleep (among other things) we don’t yet know if helping sleep will reduce the incidence of Alzheimer’s disease.

References:

Sharma, V. K., Sharma, P., Deshmukh, R., & Singh, R. (2015). Age associated sleep loss: a trigger for Alzheimer’s disease. Klinik Psikofarmakoloji Bulteni, 25(1), 78-88. doi:10.5455/bcp.20140909070449

Spira, A. P., Gamaldo, A. A., An, Y., Wu, M. N., Simonsick, E. M., Bilgel, M., … & Resnick, S. M. (2013). Self-reported sleep and β-amyloid deposition in community-dwelling older adults. JAMA neurology, 70(12), 1537-1543.