Every night, people go to sleep and rest for hours. They need to sleep during the night so that they are well-rested and full of energy in the morning. The proper rest is crucial for coping with different challenges that await us during the day. We all know what it means to sleep. However, do we know how it works?
In the past, people believed that sleep is a period of unconscious rest. However, it is not true; it is far more complicated than that. Getting enough sleep is crucial as it enables our mind and body to rejuvenate. When we hit the sack, we go through a few sleep cycles, and each of them consists of five stages. Each stage has a unique purpose, such as hormone regulation, muscle recovery, and memory consolidation. We need to wake up at the end of a cycle if we want to feel the most rested and full of energy. If we are sleep-deprived, our bodies will be deprived of essential elements necessary to help us deal with daily challenges. A sleep cycle is a period of time it takes us to go through all stages. On average, individuals go through four to six cycles during the night, and each of them lasts between 90 and 120 minutes.
The first stage of sleep is called a transitional phase. During this stage, we are in and out of consciousness, and can be awakened easily. If we wake up, we will feel like we haven’t slept at all. It usually lasts for 5-10minutes, and we can sometimes experience a falling sensation and jump suddenly, which is known as hypnic myoclonia. Individuals with irregular sleeping habits tend to experience it more often than those with good habits. Our breathing slows down during this stage, and brain temperature and blood pressure decrease. Also, our eyes roll a bit, and we may open our eyelids slightly.
When this stage kicks in, our bodies are slowly preparing to enter deep sleep (stages 3 and 4). It lasts for 20 minutes, and during this period our eye movements stop, and brain waves and metabolic functions slow down. Body temperature also drops a bit, and its activity is reduced. It is referred to as light sleep together with the first stage. However, it is more difficult to wake up, compared to the previous period.
Stages 3 & 4
These two stages are also known as deep sleep, and they are the hardest to wake up from. If someone wakes you up during this period, you will be groggy and disoriented. They are also known as slow wave sleep as our brain waves slow down. Blood pressure drops even more during this period, and our breathing becomes slower and deeper. Our bodies become immobile, and there is no eye movement. These two stages last up to 45 minutes and are crucial to body rejuvenation. Growth and appetite control hormones are released to replenish tissues and muscles, and to limit the feeling of excessive hunger, which aids in the prevention of over-eating.
This stage is the only one characterized by REM or rapid eye movement. We dream during this period, and our brain and other body systems are very active, whereas our muscles are relaxed. During stage 5 our mind energizes itself, our blood pressure and heart rate increase, and our breathing becomes shallow.