Everyone needs proper sleep, and even children know this. A person spends a third of his life in sleep. Chronic lack of night rest provokes ailments, irritability and even illness. A reasonable question that arises is “why do you need to sleep and why does a person need such a long sleep time?” New research released last year attempts to answer this question and describes brain activity that was not previously known and studied. In addition, sleep is also regulated by hormones, the deficiency or excess of which negatively affects the quality of rest.
Sleep time: before and now
The influence of civilization is visible in many areas of human life, it also affects his sleep. According to the latest Gallup poll in 2013, almost 40% of Americans are sleep deprived, and 70 million people have a sleep disorder diagnosed and in need of treatment. Today, the average sleep time at night for adults is 6.8 hours, while in the 1940s it was 8 hours. In 1952, 89% of the adult population had adequate sleep. Currently, only 59% of adults have adequate sleep on a consistent basis. This means that almost one in two people does not get adequate or quality sleep on an almost daily basis.
What diseases can be caused by lack of sleep?
Chances are, almost everyone has been in the category of bad sleepers at some point in their lives. Many people know the state when you need to get up early in the morning without getting enough sleep, or due to the fact that sleep was intermittent during the night. At best, many feel disorganized and lethargic, a little angry. For many with occasional sleep deprivation, coffee or breakfast helps to cheer up. But it is possible that many symptoms or problems arise, ranging from irritability, learning difficulties, poor memory, inadequate decision-making, absent-mindedness, to more severe disturbances in well-being and even provoking illness.
Chronic sleep disorders provoke headaches and migraines, constant weakness and lethargy, problems with blood pressure, obesity. Such people often have colds and flu due to a weakened immune system, cardiovascular diseases, and an increase in nocturnal urination is typical. Inflammatory bowel disease, diabetes, cancer, dementia, depression, hormonal imbalance and other problems can be provoked.
The main problem is that if a person does not get enough sleep, it affects every process of the body at one level or another, tissue repair is inefficient.
Features of the brain: a system for removing “garbage”
The brain has a unique “debris removal” system separate from the rest of the body. It includes the cerebrospinal fluid of a specific composition that surrounds the brain and spinal cord. It does not interact with the lymphatic or circulatory system outside of its region (within the blood-brain barrier). Researchers, through animal experiments, have identified specific pathways in the brain that are involved in the “junk removal” process. They are part of the glymphatic system, which includes a system of glial cells and lymphatic capillaries that form the unique “lymphatic system” of the brain.
Why does the brain need sleep?
This formation works like a sewerage system in the brain to remove waste products. Sleep stimulates the glymphatic system, activating a newly discovered mechanism that is unique in its own way. During sleep, neurons contract by about 60%, and channels throughout the brain and between cells enlarge and fill with cerebrospinal fluid. Surrounding glial cells activate their pumping systems, push cerebrospinal fluid through these additional spaces, and flush out the resulting metabolites. This waste fluid is eventually excreted outside the brain and spine into the vascular circulation and some of it into the lymphatic system, mixing with the rest of the body’s waste materials.
When a person is awake, these pathways close and the cerebrospinal fluid returns to its original homeostatic function. It surrounds the surface of the brain and spinal cord, providing protection against dehydration, and is involved in the metabolism of the central nervous system. During wakefulness, the cleaning process occurs only within 5% of its performance compared to sleep. This process is so energy-intensive that it can only fully work when deep sleep sets in.
Genes and impaired hormone synthesis
Other studies show that sleep deprivation has serious consequences for many other aspects of life and health, some of which have not yet been studied. For example, a 2013 study found that insufficient sleep and disrupted circadian rhythms cause more than 700 genes to be turned on or off incorrectly. These gene signals have been associated with circadian rhythm mechanisms, sleep homeostasis, oxidative stress, and metabolism. Lack of adequate quality sleep leads to RNA/DNA modification, gene polymorphism, changes in basic metabolic function, inflammation, immune imbalance, and higher levels of stress responses.
Sleep deprivation is also known to cause changes in the synthesis of several hormones. For example, it leads to an increase in the synthesis of insulin and a decrease in the sensitivity of cells to it, a decrease in the level of growth hormone. Other hormones also suffer — cortisol levels increase, the amount of prolactin and leptin, DHEA decreases. Sleep deficiency significantly affects thyroid hormones — the synthesis of TSH and free T4 is disrupted depending on the duration of sleep disturbances, and testosterone is reduced by as much as 70%.
A necessary component for brain recovery, BDNF (brain-derived neurotrophic factor), is also reduced by 33% with sleep deprivation and excessive activity without rest. This negatively affects how these hormones are used, leading to an increase in inflammatory markers such as C‑reactive protein and inflammatory cytokines. The consequences of these changes are very serious.