Stages of Sleep

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The earth revolves around the sun creating a period of sun light and darkness.  This cyclic pattern separates our days into daytime and nighttime.    Our bodies developed a daily rhythm that functions within the earthy cycle, known as the circadian rhythm.  The circadian rhythm relies on the sunlight and lack of sunlight in order to regulate our sleep and wake periods.  When the sun sets, our brain begins to release chemicals that prepare your body for sleep.  Once asleep, your bodies will undergo various stages and cycles.

REM Sleep

Sleep is divided into two distinct periods referred to a REM (Rapid Eye Movement) and nREM (non-rapid eye movement).  What does eye movement have to do with sleep?   Just as the name suggests, REM sleep is the period of your sleep where your eyes move swiftly in a side to side pattern.  This is a distinguishing feature, because also during this period everything else in your body, except respiration, remains paralyzed.  REM sleep is the stage where you experience vivid dreams, problem solve, and brain refreshes itself, and should account for 20-25 % of your total sleep time.  The REM cycles become more frequent and longer as your sleep time becomes longer.  Lack of REM sleep over time may cause mental impairment such as memory loss, dementia, confusion, and has even been linked with Alzheimer’s disease.  

nREM Stage 1

Non-REM sleep is broken into several different stages.   In stage one, your muscles begin to relax and your body temperature drops.  You begin to drift in and out of wakefulness.  Stage 1 sleep usually accounts for 4-5% of total sleep time.  This percentage increases as we get older.  

nREM Stage 2

During stage two sleep, transition sleep, your heart rate begins to decrease along with the brain waves.  Your body prepares for the next and final stages of nREM sleep.  This period usually accounts for 45-55% of total sleep time.  Short “power naps” will often involve stages 1 and 2 of nREM sleep and can enhance concentration, mood, and sharpen motor skills.  

nREM Stages 3 and 4

This period is commonly referred to as delta or slow wave sleep.  The name is derived from the frequency of the brain waves. During this phase, the brain waves become slower in frequency and larger in amplitude.  It’s difficult to waken someone within this period, or if awaken, they may seem disillusioned or confused.  This period is critical in children and can account for as much as 50% in their total sleep time.  This period decreases as we age and eventually becomes absent.  

Sleep Interrupted

Are you finding yourself waking up multiple times in one night?  If any period of your sleep cycle is disrupted, it can have consequences to your health.  Sleep essential your daily healing and recovery.  During sleep, your body relies hormones and chemicals helping to repair itself and restore energy.  Breaks in this cycle and lack of sleep can result in chronic inflammation and fatigue.  Lack of sleep has been linked to serious health problems such as diabetes, high blood pressure, dementia, fibromyalgia, head and neck pain, and sexual dysfunction.   If you or a loved one suffers from sleep deprivation, find a sleep specialist nearby to begin the road of recovery and health.