Stages of Sleep

Yesterday I started a discussion on lack of sleep and unrefreshing sleep in CFIDS patients. You can click here to read the topic.  Today I wanted to discuss the different stages of sleep and how these stages affect CFIDS.

There are two types of sleep:  REM (rapid-eye movement), which is characterized by dreaming, and non-REM, which is divided into four stages.

Stage 1 – This is the transition between wake and sleep.

Stage 2 – Referred to as baseline sleep

Stages 3 & 4 – Deepest stages of sleep (delta sleep)

Healthy humans cycle amount these stages of sleep five to six times, with each cycle lasting about 90 minutes.  As we begin to fall asleep, the first three stages of sleep are entered rather quickly.  Once we enter stage 4, delta sleep, this is compared to a coma because our heart rate and breathing slow and our bodies are still.  Most of our sleep in stages 3 and 4 occurs during the first three hours of sleep; afterward we mainly transition between stage 2 and REM sleep.  If this pattern is disrupted, we wake unrefreshed and have trouble functioning during the day.

The most commonly cited CFIDS research findings are an intrusion of fast “alpha” waves into the delta stages of sleep and a decrease in the duration of stage 4 sleep.  It is logical that both of these disruptions to the most restful stages of sleep might result in fatigue and unrefreshing sleep.