“Sleep that soothes away all our worries. Sleep that puts each day to rest. Sleep that relieves the weary labourer and heals hurt minds. Sleep, the main course in life's feast, and the most nourishing.” Macbeth: William Shakespeare.
Why do we sleep? In simple terms, the time we spend asleep gives our bodies and out minds a chance to relax and reset. Whilst we sleep our bodies can concentrate on healing damage sustained throughout a busy day and our minds can sort and file memories created during the day. When we are young sleep is also linked with growth, with babies in particular tending to sleep more when they are going through a growth spurt.
As the quote above shows, even in Shakespeare’s time the importance of a good night’s sleep was understood. But, in this 24/7 life have we lost sight of this; seeing sleep more as something to get through rather than an important contributor to health and wellbeing?
If we have, we might want to think again! It has long been observed that those suffering from certain forms of dementia, including Alzheimer’s, can experience poor sleep patterns. Now an increasing body of research is revealing the way in which poor sleep patterns may contribute to the initial development of Alzheimer’s.
One 2018 study [1] looked at the potential effect of sleep deprivation on the build up in the brain of a metabolic waste product, beta-amyloid. It is already known that clumps of this waste product known as amyloid plaques are present in those with Alzheimer’s disease, with the plaques hindering vital communication links between neurons in the brain.
The researchers scanned the brains of healthy study participants both after a good night’s sleep and after having gone thirty-one hours without sleep. They found that following just one night of sleep deprivation beta-amyloid increased by around 5%. Interestingly, that increase was most prevalent in the thalamus and hippocampus; areas which are known to be particularly vulnerable to damage in the early stages of Alzheimer’s disease.
That study was reinforced by two studies in 2021.
The first [2] revealed that when other factors were excluded, those who slept for six hours or less in their 50s and 60s had a thirty percent increased risk of developing dementia in later life.
The second study [3] concluded that each additional hour of sleep (measured up to ten hours of sleep per night) was associated with a 6% reduction in beta-amyloid levels. In effect, the time spent asleep enabled the brain to flush out these potentially harmful products. That study also highlighted that sleeping in the daytime not only did not make up for a lack of night-time sleep; it could also add to the levels of harmful plaques deposited.
Further research is underway, but some scientists have suggested that ensuring a good night’s sleep may be one way in which we can not only reduce our chances of developing Alzheimer’s but also stave off the early development of the disease. A very good reason indeed to get a good night’s sleep.