Most people perceive sleep as a short “pause”, a time for rest and a decrease in the body’s activity. But in fact, at night, the body begins a large-scale physiological work, without which no system can fully function. Sleep is not a luxury or a passive process, but a complex mechanism of recovery, detoxification and hormonal stabilization.
Modern research proves that treating sleep as a secondary need is one of the main causes of chronic fatigue, psychological disorders, and a wide range of somatic diseases.
Why does the body need sleep?
During a night's rest, the glymphatic system, the brain's "garbage disposal," is activated. It is it that removes toxins, in particular beta-amyloid, an excess of which is associated with the development of Alzheimer's disease. If a person does not get enough sleep, the brain simply does not have time to cleanse itself, and this directly affects cognitive functions.
In the deep phase of sleep, long-term memories are formed, information is structured and transferred from short-term memory. In the REM phase, the brain "loses" the emotions of the day, normalizes reactions to stress, reduces excessive neural connections. That is why after quality sleep we think more clearly, learn more easily and react calmly.
Hormones, immunity and tissue repair
Up to 90% of growth hormone is secreted during nighttime sleep. In adults, it is responsible for tissue regeneration, which is why athletes and people after surgery recover faster if they sleep for at least 8–9 hours.
Sleep regulates the hormones that control hunger and satiety, leptin and ghrelin. Sleep deprivation upsets the balance and often leads to overeating and weight gain. It also alters insulin sensitivity, which increases the risk of type 2 diabetes.
The immune system is most active at night: this is when most T-cells and cytokines are produced. It has been proven that people who sleep less than six hours are 4–5 times more likely to get a cold after contact with a virus.
Sleep as a cure for the heart
Blood pressure and heart rate naturally decrease by 10–20% at night. This is a necessary “respite” for the cardiovascular system. Chronic sleep deprivation disrupts this mechanism and over the years increases the likelihood of hypertension, heart attacks, and strokes.
How dangerous is lack of sleep?
Not getting enough sleep doesn't just have visible consequences—fatigue, poor concentration, and irritability. The risks go much deeper:
• after one night of sleep deprivation, beta-amyloid accumulates in the brain, a key factor in the development of Alzheimer's disease;
• people who sleep less than seven hours are more likely to suffer from obesity;
• short sleep increases the risk of heart attacks by 20%;
• sleep disorders are one of the factors of strokes;
• lack of sleep increases the risk of injuries, accidents and mistakes at work.
Insufficient sleep is a systemic problem, not a small thing that can be "fixed with coffee."
What harms sleep?
Experts emphasize: the quality of sleep is determined by daily habits. The most common mistakes:
• using smartphones and laptops before bed — the bright light from the screen disrupts melatonin production;
• work thoughts, news, and stress activate the brain and prevent you from falling asleep;
• caffeine after dinner shifts your sleep cycle by hours;
• lack of balance between work and personal life contributes to increased stress.
Sleep problems are increasingly common in children and adolescents, which has already led to discussions about changing school start times.
How much sleep do you need?
Sleep needs depend on age:
• infants: 12–16 hours;
• preschoolers: 10–13 hours;
• school-age children: 9–12 hours;
• teenagers: 8–10 hours;
• adults: at least 7 hours.
There is no specific norm for newborns, but it is usually 14–17 hours per day.
Experts advise to focus not only on standards, but also on your own well-being. A stable regime helps the body determine the ideal duration of rest and maintain optimal functioning of all systems.
