What are the sleep stages and sleep cycle?

Sleep is a fundamental human need, as essential as air, water, and food. But not all sleep is created equal. To truly understand the importance of sleep, we must delve into the intricate dance of sleep stages and cycles. Moreover, we must recognize the long-term health implications of neglecting quality sleep.

The Sleep Stages

Sleep is divided into several stages, each with its own unique physiological characteristics:

1. Non-REM Stage 1 (N1):
   • Duration: A few minutes.
   • Characteristics: Transition from wakefulness to sleep. Light sleep.
   • Physiological changes: Slowing heartbeat, decreased muscle activity, and slower eye movements.
2. Non-REM Stage 2 (N2):
   • Duration: 10-25 minutes.
   • Characteristics: Deeper than N1 but still considered light sleep.
   • Physiological changes: Further decrease in heart rate and body temperature. Eye movements stop, and brain waves become slower, with occasional bursts of rapid waves called sleep spindles.
3. Non-REM Stage 3 (N3):
   • Duration: 20-40 minutes.
   • Characteristics: Deep, restorative sleep. It's hardest to be awakened from this stage.
   • Physiological changes: Extremely slow brain waves called delta waves emerge, interspersed with smaller, faster waves. It's during this stage that the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system.
4. REM (Rapid Eye Movement) Sleep:
   • Duration: Starts about 90 minutes after falling asleep and lasts around 10 minutes in the first cycle, increasing in duration in later cycles.
   • Characteristics: Most dreaming occurs here. The brain becomes more active, but the body becomes more relaxed and immobilized.
   • Physiological changes: Rapid eye movements, increased respiration rate, and brain activity similar to that seen while awake.

The Sleep Cycle

During the night, a person typically goes through several sleep cycles, each lasting about 90 minutes. While the duration of each stage remains relatively constant throughout the night, the amount of time spent in each stage can vary. In the first half of the night, the majority of sleep time is spent in N3, the deepest stage of non-REM sleep, and N2, while the amount of REM sleep is relatively short. In the second half of the night, the duration of N3 decreases, and the duration of REM sleep increases, with the final cycle having the longest REM stage. This sleep cycle pattern is essential for the body's restorative processes and overall well-being. Disrupting this natural cycle, whether it is due to sleep disorders or poor sleep habits, can have negative consequences on health and daily functioning.

Sleep is an essential human need that is crucial for overall health and wellbeing. The sleep stages and cycle are intricate and play an important role in the body's restorative processes. Neglecting quality sleep can have significant health implications such as cognitive impairments, mood disorders, weakened immunity, weight gain, increased risk of chronic diseases, hormonal imbalances, and reduced libido. It is important to prioritize adequate and quality sleep to maintain good health and prevent these negative outcomes.

For more information, contact us at:
Phone: 0-2677-7077
Facebook: ADDLIFECenter
Line: @addlife
www.add-life.org