Stages Of Sleep
Stages of Sleep
The EEG (Electroencephalogram)of a waking person is clearly different than that of a sleeping person. The difference in EEG patterns that occur during sleep has made it possible to divide sleep into five different stages.
Stage One We experience stage one of sleep when we are half asleep and half awake; our eyelids feel heavy, we feel groggy and suddenly without notice we fall asleep. Stage one counts for more or less 5% our total sleep during the night. Stage one is characterized by the presence of theta waves, slower and stronger waves than alpha and beta waves. Theta activity is more regular and has higher voltage than alpha and beta waves.
An example of this would be that sometimes while I am reading . I would find myself drifting off to sleep, then suddenly wake up and continue reading in the same place, and be very alert. This can occur more than once especially if I am tired or during an intense period of studying.
Stage Two In stage two, we still get theta waves plus K complexes and sleep spindles. Sleep spindles are sudden and intense bursts of electrical activity that last for a second or two. K complexes are also sudden and sharp waves of a longer frequency.
During this stage if someone tried to wake me, I have great difficulty awakening, however I can easily be awakened if a door slams, or a dog barks or by any other loud sounds.
Stage Three and Four or Slow Wave Sleep After about fifteen minutes, we are ready to enter stage 3. When we enter Stage 3, our brain activity is synchronized. This means that big groups of cells are firing at about the same time. This unified activity in the brain is represented in the EEG recordings by large waves called delta waves. Delta waves are the slowest and strongest waves that our brain produces. Stage 3 has about 20-50% of delta waves. Stage 4 is all delta activity. Stage 3 and 4 are also called slow wave sleep because of the appearance of delta waves. A
The EEG (Electroencephalogram)of a waking person is clearly different than that of a sleeping person. The difference in EEG patterns that occur during sleep has made it possible to divide sleep into five different stages.
Stage One We experience stage one of sleep when we are half asleep and half awake; our eyelids feel heavy, we feel groggy and suddenly without notice we fall asleep. Stage one counts for more or less 5% our total sleep during the night. Stage one is characterized by the presence of theta waves, slower and stronger waves than alpha and beta waves. Theta activity is more regular and has higher voltage than alpha and beta waves.
An example of this would be that sometimes while I am reading . I would find myself drifting off to sleep, then suddenly wake up and continue reading in the same place, and be very alert. This can occur more than once especially if I am tired or during an intense period of studying.
Stage Two In stage two, we still get theta waves plus K complexes and sleep spindles. Sleep spindles are sudden and intense bursts of electrical activity that last for a second or two. K complexes are also sudden and sharp waves of a longer frequency.
During this stage if someone tried to wake me, I have great difficulty awakening, however I can easily be awakened if a door slams, or a dog barks or by any other loud sounds.
Stage Three and Four or Slow Wave Sleep After about fifteen minutes, we are ready to enter stage 3. When we enter Stage 3, our brain activity is synchronized. This means that big groups of cells are firing at about the same time. This unified activity in the brain is represented in the EEG recordings by large waves called delta waves. Delta waves are the slowest and strongest waves that our brain produces. Stage 3 has about 20-50% of delta waves. Stage 4 is all delta activity. Stage 3 and 4 are also called slow wave sleep because of the appearance of delta waves. A