Sleep fills a third of our lives. During sleep, thousands of brain and nervous system processes and extensive hormonal activities take place that affect our health. Sleep is critical not only for relieving fatigue but gaining strength for the next day. In recent years, more and more evidence has been discovered that a lack of sleep not only impairs the body’s daily functions, it is simply dangerous.
Clinical studies indicate that insufficient sleep is associated with an increased risk of dementia, hypertension, obesity, diabetes, and even depression. Despite this, surveys conducted in recent years have shown that on average, people in the Western world are getting less sleep than the nightly recommended hours. According to some surveys, adult Israelis sleep an average of six hours or fewer a night. The situation has worsened since October 7 as well as a significant increase in the consumption of sleep medications, according to pharmacy data.
Our night consists of several sleep cycles, each lasting about an hour and a half. Each such stage includes four phases. The first stage of sleep is called N1, non-rapid-eye movement sleep. It is typical of the beginning of sleep and lasts for ten minutes, in which we begin the process of falling asleep. At this stage, there may be false visions called hypnagogia and the eye movements are slow as we begin to lose consciousness. At this stage, it is still easy to wake the sleeper.
The next stage is called N2, and lasts about 10 to 25 minutes. The second stage is responsible for about half of the entire night’s sleep. At this stage we gradually lose awareness of the environment and brain activity slows down. When a person in this sleep stage is woken up, he will report that he was indeed asleep.
Stage N3 is the stage of deep sleep where we spend about a quarter of our total night sleep. This phase gets shorter throughout the night. The first sleep cycle lasts about 40 minutes and towards awakening it shortens to only a few minutes. In this state, the muscles are relaxed, the body temperature drops, and the awareness of the environment is almost non-existent. It is very difficult to wake up a person at this stage. If they do get woken up, they are still drowsy and experience a condition called “sleep inertia.” For this reason, for example, people suffering from ADHD have a delayed secretion of melatonin, the biological hormone, in the morning they are still in an extensive N3 phase and it is very difficult to wake them up for school.
The last stage is REM, rapid eye movement. At this stage, the slow brain activity becomes more vigorous and the heart rate increases along with rapid eye movement. However, the muscles are completely paralyzed except for the fast-moving eye muscles, the muscles in the heart, and the muscles that support breathing.
Dreams usually appear in the REM stage. This stage is responsible for about a quarter of our total sleep and unlike stage N3, it gets longer during the night. These dreams are longer, appear in the morning hours,
