How sleep provides essential maintenance for the brain
By Tina Stibbe
After a good night’s sleep, you start the day clearheaded and well rested. But there’s a lot more going on during sleep than simple rest for the body and mind. The biological function and role of this bodily shutdown is gradually being deciphered with many interesting findings.
So do we really need sleep? It serves neither the purpose of reproduction nor the search or consumption of food, and therefore seems dispensable from an evolutionary point of view. Nevertheless, we can’t live without it and sleep deprivation is known to cause severe physical and mental problems. Indeed, sleep maintains the function of the entire body through homeostasis.
Lack of sleep impacts the brain’s nutrient supply
The optimal amount of sleep to maintain proper personal performance is not the same for everyone. Some people can perfectly function on five to six hours a night, while others need no less than eight or nine hours of sleep to be fully operational.
Staying permanently below this magic number can lead to a series of dysfunctions in body processes – which in turn impact the ageing of our body. The longevity of our body functions and metabolic activity depends on biological factors such as genetics, but also environmental influences like diet, exercise and sleep.
One central issue when it comes to sustaining body processes is the maintenance of a healthy blood flow, which is hindered by vascular ageing. The ability to narrow and widen blood vessels is crucial for the optimal supply of nutrients and oxygen to vital organs.
It has been shown, that a range of molecular pathways involved in vascular ageing, especially in the brain, are highly impacted by sleeping patterns. A long-term lack of sleep leads to a narrowing of the blood vessels in the brain and thereby cutting the brain off from the essential molecules it needs to function properly, in turn increasing the risk for vascular dementia.
Our memory is built during sleep
The role of sleep goes way beyond proper blood flow for the brain, though. Sleep disruption can cause severe problems with our cognitive abilities, due to the fact that during sleep we consolidate what we have learned during the day.
While we are awake, we acquire memories and learn new things, that are encoded in our short-term memory, during sleep this information is reinforced in our long-term memory and can then be accessed again during wakefulness whenever we may need it.
Denying the body a sufficient amount of sleep, especially over a longer period of time, causes impaired functioning in attentional or working memory tasks, because the brain doesn’t have a chance to strengthen its learnings.
The brain “cleans house” while we sleep
So, by no means is the brain inactive while we sleep. The overall metabolic demand is indeed reduced compared to when we are awake, however the brain uses this time of lower activity to get rid of waste products.
It has recently been suggested, that while the brain is not actively turning over nutrients to fuel daytime tasks, it clears out metabolic byproducts from the space between the cells. These redundant molecules are washed out via the brain fluid, which flows more rapidly through the brain tissue and adjacent to the brain’s blood vessels during sleep time. Notably, these carted off particles also include harmful peptides, such as Amyloid beta, a molecule linked to Alzheimer’s Disease.
Sleep hygiene is important
Naturally, with age, sleep time becomes shorter with more interruption phases and poorer quality. However, other factors can also influence sleeping patterns, such as the sleeping environment. Therefore, sleep hygiene is crucial to improve or maintain healthy sleep.
Lifestyle choices like consuming excessive amounts of alcohol, caffeine or drugs, but also shift work or jet lag can alter sleep quality. In addition, elevated levels of noise and light can hinder healthy sleep.
Therefore, it is advised to set up your bedroom to be quiet and dark as well as at the correct temperature. Large meals, caffeine and alcohol should be avoided before bedtime, which should be consistent – so roughly around the same time each night.
A good workout can also enhance sleep, as daytime exercise can help you fall asleep more easily. Last but not least, and this seems more relevant in the 21st century than ever before, the presence of electronic devices like a TV or smartphones should be banned from the bedroom altogether.
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