Understanding Normal Sleep Is The Key To Understanding Any Sleep Disorder
The key to understanding any sleep disorder is understanding normal sleep. Just as there are there are different types of sleep disorders, there are different types of sleep studies. There are different indications as well. Here are three of the most common sleep studies used to identify a sleep abnormality: a PSG (Polysomnogram), a MSLT (Multiple Sleep Latency Test), an Actigraphy, and MWT (Maintenance of Wakefulness Test). There are times where no sleep study is needed. Clinical history can be sufficient. An important concept in treatment of sleep disorders is identifying the appropriate sleep disorder. But before we are able to identify or understand sleep disorders we have to understand what Normal Sleep is.
Normal Sleep
The Parts Of Normal Sleep
With Normal Sleep, there are four parts: Awake, Sleep Onset, Non-REM Sleep, and REM Sleep.
Awake – Bar is at top. Not only do you see bar of Awake before sleep onset and once the night is over, but wake intrusions are normal.
Sleep Onset – Note that it can be a normal thing to not fall asleep once you get in bed. Sleep onset of 30 minutes is considered normal.
Our Powerful Wake & Sleep Drives
As one is awake, brain metabolism of glucose yields waste product of adenosine. Buildup of adenosine occurs throughout the day. Adenosine gives a feeling of fatigue and sleepiness (Caffeine inhibits the accumulation of adenosine). This is part of our Homeostatic Process and Body Process. We also have another process. It is called our Circadian Process and Environmental Process. As light enters through the retina-thalamic pathway to the suprachiasmitic nucleus we suppress Melatonin secretion. But when the light is removed (AKA nighttime), we begin to secrete Melatonin. The Homeostatic Sleep Drive leads to an accumulation of adenosine, resulting in a climax of feeling of fatigue and sleepiness. This occurs around a time when environmentally there is less light, and there is no longer suppression of the sleep promoting neurotransmitter, Melatonin. This results in a powerful urge to sleep. This is why it can also be hard for someone to try to sleep earlier then they are accustomed to and why during sleep deprivation one may fall asleep earlier than normal.
Getting Enough Sleep
– 12 month old should get 12 hours (including nap time)
– 10 year old should get 10 hours 9th grader through high school should get 9 hours
– 8 hour work days, 9-to-5 job, you should get 8 hours
– 70’s (geriatric) should get 7 hours (plus nap time)
Sleep Curve
Just as the growth curve is broad, the Sleep Curve is even broader. However it is inverse. The sleep duration from infancy through first year of life and toddler has the higher range on the bell curve.
Insomnia cures. Insomnia escape. <Video Link>
Parenting and sleep. Sleep in infants. <Video Link>
