Understanding Normal Sleep

Patient Expert

If you are dealing with insomnia or any other type of sleep disorder, you may wish that you could just sleep normally. But, what is normal sleep?

Normal sleep is the ability to fall asleep within a few minutes up to 30 minutes once you are in bed – and staying asleep. Normal sleep also involves going through four stages of sleep. These four stages will be repeated several times over the course of a night.

Stage One of Sleep

This is the lightest of all of the sleep stages. It takes up roughly 10 percent of your sleeping time. This is the period of time that your body begins to drift off to sleep. During this time you may experience a type of dreaminess, similar to daydreams. Yet, they are not true dreams. During stage one it can be common to experience sensations and feelings. For instance, you may think you hear something you don’t, such as a phone ringing. Or, you may have a feeling of falling or your body may jerk or have sudden muscle contractions that startle you.

Stage Two of Sleep

During stage two of sleep, you are generally not aware of outside stimuli. Most people spend the majority of their sleep time in this stage. This stage is when your heart rate begins to slow and your body temperature begins to drop. Your brain also begins to create rhythmic, rapid brain waves for short periods of time.

Stage Three of Sleep

It is believed that stage three of sleep is the most restorative state of sleep. It is the transition stage between light sleep and deep sleep. During this stage, brain waves are slow. You may not awaken to outside stimuli unless it is intense.

Stage Four of Sleep

Stage four of sleep is considered the active stage of sleep. It is known as REM (rapid eye movement) sleep. It is during this stage of sleep that your brain is the most active and dreams occur. Oxygen consumption and arousal is higher than when the body is awake.

Studies have shown that stage four of sleep is reached approximately every 90 minutes in normal sleep. During this stage of sleep your voluntary muscles are relaxed, or seemingly paralyzed. It’s believed this 'paralysis' of voluntary muscles, such as the arms and legs, is to prevent you from acting out dreams in the physical realm while asleep. This paralysis protects the body, and others, from harm during this dreaming stage.

Sleep Cycling

The body goes through stage one through four of the sleep cycle, and then repeats the stages throughout the night. However, the different stages of sleep do not repeat in sequence. Studies have shown that after stage four is reached, the body generally goes back to stage three, then two, then back to three, and back to REM sleep.

As the body cycles through the stages, each cycle lasts longer. For instance, during the first cycle of sleep you may only remain in stage four, or the dreaming stage, for 10 minutes or so. On cycle three or four you may remain in this stage for up to an hour.

Going with a small amount of sleep, or only sleeping for short bursts at a time, does not enable the sleep cycle to run its proper course. This is why we need to sleep for long periods of time. When the normal sleep cycle is out of whack and insomnia is taking over, it impacts all areas of life – physically and mentally.

To learn more about how to regulate sleep, and improve your sleep if you're suffering from insomnia, you can enroll in my free online sleep training course.