Why Do We Have to Sleep?

Most of us see sleep as a passive time period: The body rests, energy is collected. But the truth is much more fascinating! Sleep is one of the times when our brain works most intensively. While sleeping:

The brain deletes “unnecessary” information

Transfers important memories to long-term memory

Reinforces what we have learned

Cleanses toxins

There are special cleaners in the brain called glial cells . These cells come into play when we are asleep and clean up toxic waste such as beta-amyloid that accumulates between neurons. (If this substance accumulates, it increases the risk of Alzheimer's!)

What are the stages of sleep?

REM sleep (Rapid Eye Movement): Even if the eyes are closed during this phase, the pupils move rapidly from side to side, hence the name. Most dreams occur here. The brain is almost as active as if it were awake. Learning, memory, emotional regulation and creativity develop during this phase. Its deficiency manifests itself with emotional instability, learning and memory problems, decreased creativity and an increased risk of depression. REM sleep is a “necessary for survival” phase.

Non-REM sleep : Deep sleep part. The body repairs, growth hormones are released.

This cycle repeats itself 4-5 times each night. Eye movements slow down, heart rate slows down, body temperature drops, “sleep spindles” and “K-complexes” form in the brain, which protect the brain against external stimuli, growth hormone is secreted here, tissue repair and immune system strengthening occur here.

What does less sleep cause?

Memory problems

Impaired decision-making ability

Insulin resistance → Diabetes risk

Weakened immune system

Increased depression and anxiety

Sleeping less than 6 hours can be an invitation to chronic diseases.

What is the ideal sleep duration?

According to scientists:

Adults: 7-9 hours

Teenagers: 8-10 hours

Children: 9-12 hoursBut it's not just the duration that's important: It's the quality of sleep! If you can get into the deep sleep phase throughout the night, that's when real rest begins.

In short, the first half of sleep is usually more deep NREM sleep, while the second half is more REM sleep. In other words, the first hours are like physical recovery, the last hours are like emotional recovery!