Sleep Cycle

Sleep cycle refers to the pattern of sleep stages that a person progresses through when sleeping

❖ STAGES OF SLEEP

➢ NON-REM sleep stage-1

Characteristics of this stage:

(Usually less than 10 minutes ,Stagebetween wakefulness and sleep ,Dreaming is relatively rare ,Easily disrupted sleep ,The sleeper may be aware of sounds and conversations)

➢ NON-REM sleep stage-2

Characteristics of this stage:

(Awareness of the outside world begins to fade completely ,It typically constitutes about 45%-50% of total sleep time for adults)

➢ NON-REM sleep stage-3

Characteristics of this stage:

(Essentially cut off from the world and unaware of any sounds or other stimuli ,neuronal activity is at its lowest during stage 3 ,Dreams may present ,This is also the stage during which parasomnias like sleep-walking, sleep-talking and bedwetting occur ,It is much more difficult to wake a person during stage 3 sleep)

➢ REM sleep 

As the name suggests, it is associated with rapid (and apparently random) side-to-side movements of the closed eyes.

Characteristics of this stage:

(The majority of dreams (most memorable and vivid dreams) ,Muscles become completely paralyzed ,Breathing becomes more rapid and irregular ,High energy or oxygen consumption ,High-level active concentration and thinking m Lack of REM sleep leads to surprisingly few negative effects on behaviour, it has been shown to impair the ability to learn complex tasks)

❖ Hormones affecting sleep

1. Hormone makes us feel sleepy at night Melatonin

2. Hormone gives us a wake-up call in the morning Cortisol

❖ Factors affecting sleep cycle:

• Age 
•  Sleep deprivation
•  Food 
•  Frequently changing sleep schedule
• Stress
• Environment
• Psychological conditions like depression and their treatments