While we sleep, our brain constantly remains active, passing through different phases or steps.
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Sleepiness
This first step occurs just before we fall asleep, as we transition from wakefulness into the initial dream state. During this phase, we can still perceive our surroundings clearly through our senses (such as hearing and touch). Muscle tone weakens compared to wakefulness, and ocular movement slowly begins.
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Light Sleep
During light sleep, there is a noticeable reduction in our breathing and heartbeat. Our nervous system blocks sensory access, allowing us to disconnect from the external environment. We are now fully asleep, and it becomes more challenging to wake up.
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Transition
The transition from light sleep to deep sleep takes a few minutes. Muscle tone decreases further, but REM (rapid eye movement) sleep has not yet occurred. If we happen to wake up during this phase, we often feel confused and disoriented.
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Deep Sleep
In this stage, we are not yet experiencing dreams, but our heart rate and breathing decrease by approximately 30 percent. Deep sleep typically lasts for about sixty minutes and sets the stage for the final phase.
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REM (Rapid Eye Movement)
This phase of sleep is characterized by rapid eye movements, heightened brain activity, and the emergence of dreams. After approximately half an hour, the sleep cycle begins anew, repeating the first five phases. These cycles of slow and active sleep repeat throughout the night, occurring between four and six times, depending on a person's age.