WHAT IS SLEEP

: The natural, easily reversible, periodic state of many living things that is marked by the absence of wakefulness and by the loss of consciousness of one's surroundings, is accompanied by a typical body posture (as lying down with the eyes closed), the occurrence of dreaming, and changes in brain activity 

 Many biological processes happen during sleep: The brain stores new information and gets rid of toxic waste. Nerve cells communicate and reorganize, which supports healthy brain function. The body repairs cells, restores energy, and releases molecules like hormones and proteins.

 Sleep has been traditionally divided into 4 categories: awake, light, deep, and REM sleep. Each one plays an essential role in maintaining your mental and physical health.

 There are two basic types of sleep: rapid eye movement (REM) sleep and non-REM sleep (which has three different stages).

 Almost 50 percent of our total sleep time is spent in stage 2 sleep, while 20 percent is spent in REM sleep, and the remaining 30 percent in the other stages. During stage 1, your eyes roll slowly, opening and closing slightly; however the eyes are then still from stages 2-4 when sleep is deeper.

 

Sleep Stages

• Stage 1 non-REM sleep is the changeover from wakefulness to sleep.
• Stage 2 non-REM sleep is a period of light sleep before you enter deeper sleep. 
• Stage 3 non-REM sleep is the period of deep sleep that you need to feel refreshed in the morning. 
• REM sleep first occurs about 90 minutes after falling asleep.

It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep. Following a period of slow-wave sleep, however, EEG recordings show that the stages of sleep reverse to reach a quite different state called rapid eye movement, or REM, sleep.

 

Physiological Changes During Sleep

Many physiological variables are controlled during wakefulness at levels that are optimal for the body’s functioning. Our temperature, blood pressure, and levels of oxygen, carbon dioxide, and glucose in the blood remain quite constant during wakefulness. During sleep, however, physiological demands are reduced and temperature and blood pressure drop. In general, many of our physiological functions such as brain wave activity, breathing, and heart rate are quite variable when we are awake or during REM sleep, but are extremely regular when we are in non-REM sleep

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Breathing

Breathing slows during non-REM sleep with respiration reaching its lowest rates during deep sleep stage three. Breathing ramps up and may become irregular during REM sleep.

Heart Rate

As with breathing, heart rate begins to slow during Stage 1 and reaches its slowest pace during Stage 3. On the other hand, during REM sleep, the pulse quickens to nearly the same rate as when awake.

 

Sleep is an essential function that allows your body and mind to recharge, leaving you refreshed and alert when you wake up. Healthy sleep also helps the body remain healthy and stave off diseases. Without enough sleep, the brain cannot function properly.

 

When light seeps through our eyelids and touches our retinas, a signal is sent to a deep-brain region called the suprachiasmatic nucleus. This is the time, for many of us, that our last dream dissolves, we open our eyes, and we rejoin our real life.

 Essentially, sleep is a behavioral state. It is estimated that an individual spends approximately, one third of his lifetime in sleep. We have knowledge that sleep is part of the daily routine in everyone, even when the normal sleep and wake cycle (or pattern) is disrupted by outside factors.

 Poor sleep habits, like having an irregular sleep schedule or consuming too much caffeine or alcohol, can interfere with your sleep quality. In a study of nursing students, smoking and daily coffee consumption were two of the largest factors associated with poor sleep quality.

 Some habits that can improve your sleep health:

1. Be consistent.
2. Make sure your bedroom is quiet, dark, relaxing, and at a comfortable temperature.
3. Remove electronic devices, such as TVs, computers, and smart phones, from the bedroom.
4. Avoid large meals, caffeine, and alcohol before bedtime.
5. Get some exercise.  
6. Sleep
   
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