Sleep: recovery & restoration for the brain and body : Part 1 of 2  

By Lori Hudson Bertrand D.C., R.N.

Lori_pregnantAs some of you may know I am about 38 weeks pregnant with my second child. While sleep is vital for the body, it’s something I’m soon to be lacking!  In our busy world, you might find yourself sleep deprived as well.

Sleep–“There’s always time for that later!” How many times has sleep taken the back burner when life has gotten full and responsibilities took over? Today we are going to take a closer look into the physiological process of sleep and how it affects the body.  So, tonight when your head hits the pillow you will have a better understanding of just how important rest is for the body, mind, and overall wellbeing. 

Pictured Lori Hudson Bertrand, Photography by Christi Minter

Types of sleep: 

NREM- (Non Rapid Eye Movement)– makes up about 75% of sleep. The parasympathetic part of the nervous system dominates during NREM causing blood pressure and metabolic rate to decrease, ultimately allowing the body to relax.  

REM- (Rapid Eye Movement)–active dreaming, difficult to arouse; makes up about 20-25% of sleep. During this stage, blood pressure, body temperature, metabolic rate, pulse and respirations increase while deep tendon reflexes remain depressed. REM sleep is essential for mental and emotional wellbeing, as well as memory and optimal brain function.

Stages of sleep:


Stage I (transition) – first stage, lasting up to 5 minutes, the body is relaxing but easily awakened, makes up about 5% of sleep 

Stage II (light)- second stage in which the body is considered truly asleep, lasts about 10-30 minutes, constitutes roughly 50-55% of total sleep

Stage III- deeper stage of sleep, making it increasingly difficult to arouse, makes up about 10% of sleep 

Stage IV (delta)- deepest stage, brain waves slow down, muscles, tissues, a greater influx from the parasympathetic nervous system takes over allowing for restoration and recovery; contributes to about 10% of total sleep.

REM: Dream state- small muscle movement occurs while larger muscle movements are immobilized, respirations and pulse become irregular, gastric secretions may increase, respirations become shallow, blood pressure and heart rate increase; makes up about 20-25% of sleep.

Sleep cycle: Each nights sleep takes on a predictable pattern, moving through each of the four stages of NREM consecutively then moves back in the reverse order up to stage II.  Skipping stage I, the body enters the REM stage and then progresses to the stage II of NREM and progresses through stage III and IV.  If awakened at any point, the body returns to stage I and follows through the sleep cycle starting with stage I.


Sleep requirements: A common misconception about the standard amount of sleep a night has long been 8 hours despite variations within the population.  There is however no magic number, but rather a pattern of rest that promotes and maintains well-being.  While each person’s sleep requirements can vary, generalizations can be made:

1).Infants- 14-20 hours/day 
2).Children 10-14 hours/day 
3.)Adults 7-9 hours/day 
4).Older adults 5-7 hours/day

Those that are able to relax and rest easily may find less sleep is needed. However, listening to the body is crucial and some may find that more sleep is needed to overcome fatigue. Fatigue can be a normal physiological adaptation to protect and recover the body, but chronic fatigue can be a sign or symptom of illness.


Join me next week to take a closer look at how sleep effects the entire body, illnesses linked to sleep deprivation, and ways to get a better nights rest!  

DEFINE’s senior instructor and anatomy specialist, Lori Hudson Bertrand D.C., R.N. is a doctor in chiropractic and registered nurse.  She has a love for helping patients as they peruse their journey towards health and restoration!


Need time to unwind to start your sleeping off right, we recommend a DEFINE mind class!