When dealing with any health condition, it’s always helpful to find out more about it. For insomnia, I found it very helpful to know more about normal sleep. In this blog post, I’m going to share with you what I learned about sleep stages.
The Five Stages of Sleep
There are five stages of sleep.
In sleep stage 1, we are in a state between sleeping and waking. We feel drowsy but are easily wakened, our muscles are relaxed, and our heart rate, breathing rate, and body temperature are lower than when we are fully awake. This sleep stage lasts a few minutes.
In stage 2, we enter light sleep but we are still easily awakened. In this sleep stage, we are more detached from the external world. This sleep stage lasts about 30 to 45 minutes.
In stage 3, we enter deep sleep, or core sleep. During this sleep stage, our muscles recover from the activities of the day. It is hard to be awakened when we are in this sleep stage, which lasts about 45 minutes.
Stage 4 is a continuation of stage 3, where we enter even deeper sleep.
After stage 4, we go back to stage 2 sleep for a few minutes. Then we enter stage 5 sleep.
Stage 5 sleep is REM (rapid eye movement) or dream sleep. During this sleep stage, the brain is very active but the body is paralyzed, which is why we don’t act out our dreams. This sleep stage lasts for a few minutes up to an hour.
All five stages of sleep in sequence constitute one sleep cycle, which lasts about 90 minutes in total. People who sleep well typically go through four to six sleep cycles per night.
During the first half of the night, we spend more time in stage 3 and 4 sleep (deep sleep), whereas during the second half of the night, we spend more time in dream or REM sleep. We also tend to awaken more often between sleep stages (on average six times) during the second half of the night. If you thought this meant that you have insomnia, now you can be assured that it’s normal.
Here’s a graphic that illustrates what you just read:
http://greymattersjournal.com/wp-content/uploads/2013/11/img_main_SleepStages_01_US.jpg
How does sleep change as we age?
Infants tend to sleep for most of a 24 hour cycle. As we age, we tend to sleep less. Teenagers sleep about eight hours per night and people in midlife sleep about seven hours per night. People in their 70s usually sleep about 6.5 hours per night and usually take a one-hour nap during the day.
In addition, sleep quality tends to decline as we age. We get less deep sleep and our sleep tends to be lighter, especially for men. People in their 70s get almost no deep sleep. In fact, more older adults spend most of the night in stage 2 sleep, or light sleep, which does not mean they have insomnia.
Insomnia is not an inevitable part of aging.
In a later blog post, I will write about things you can do to improve your sleep quality at any stage of your life. Stay tuned!