Chapter 1
We continue to learn that sleep has a wide variety of benefits for the mind and body. But what is sleep? Why do we need to sleep? How can we improve the duration and quality of sleep? If you are an individual who believes they do not get sufficient sleep, it is never too late to start sleeping better.
In humans, sleep has been divided into four stages, non-rapid eye movement (NREM) and rapid eye movement (REM):
NREM STAGE 1
Transition from awake to asleep
NREM STAGE 2
Body temperature cools, heart rate slows
NREM STAGE 3
Breathing rate lowers, blood pressure drops, and deep sleep occurs
REM
Eyes move fast, and dreaming occurs
As we first start to fall asleep, we fall into stages 1 and 2 of NREM sleep, where the brain wave activity will slow down along with a decrease in body temperature. NREM sleep serves a multitude of different benefits for your brain and body. NREM sleep will help you absorb the information learned throughout the day. Deep NREM sleep will help the brain capture memories so you are far less likely to forget them. The deeper stages of NREM sleep will cycle down your cardiovascular system, with your blood pressure dropping. We also know that during deep sleep, we improve our immune system function. We reload our immunity arsenal to fend off bacteria and illness.
REM sleep is different to NREM sleep in many different ways. The key difference is that REM sleep brain waves are much more active compared to NREM sleep. REM sleep takes a lot of the stress we feel from strong emotions, and when we wake up the next day we feel better about those emotionally challenging moments. In some ways its not time that heals all wounds; rather, it’s time during REM sleep that provides emotional recharging. During dreaming, we take the information learned from the day and start to associate it with your brain.
Why Sleep?
For the average adult, the recommended duration of sleep is 7-9 hours a night. the CDC recommends a minimum of 7 hours of sleep for the average adult. Some individuals may require more sleep, closer to the 9-hour sleep need. Evidence suggests that the number of people who can survive on less than 6 hours or 5 hours a night without showing any impairment is 0%, as taken from the whole population.
