What happens when we don’t sleep enough
If sleep is cut short, the body doesn’t have time to complete all of the phases needed for muscle repair, memory consolidation and release of hormones regulating growth and appetite. Then we wake up less prepared to concentrate, make decisions, or engage fully in school and social activities.
How Does Sleep Contribute to All of These Things?
Sleep architecture follows a pattern of alternating REM (rapid eye movement) and NREM (non-rapid eye movement) sleep throughout a typical night in a cycle that repeats itself about every 90 minutes.
These are the stages of sleep.
NREM (75% of night): As we begin to fall asleep, we enter NREM sleep, which is composed of stages 1-4
N1 Between being awake and falling asleep, Light sleep
N2 Onset of sleep, becoming disengaged from surroundings with regular breathing and heart rate. The body temperature drops.
N3 Deepest and most restorative sleep, the blood pressure drops, breathing slows, muscles relax. Tissues regenerate with increased blood flow and energy is restored and Human Growth Hormone is released.
REM (25% of night): First occurs about 90 minutes after falling asleep and recurs about every 90 minutes, getting longer later in the night
- Provides energy to the brain and body
- Supports daytime performance
- The brain is active and dreams occur
- Eyes dart back and forth
- The body becomes immobile and relaxed, as muscles are turned off
- In addition, levels of the hormone cortisol dip at bedtime and increase over the night to promote alertness in the morning.
Sleep helps us thrive by contributing to a healthy immune system, and can also balance our appetites by helping to regulate levels of the hormones ghrelin and leptin, which play a role in our feelings of hunger and fullness. So when we’re sleep deprived, we may feel the need to eat more, which can lead to weight gain.
The one-third of our lives that we spend sleeping, far from being “unproductive,” plays a direct role in how full, energetic and successful the other two-thirds of our lives can be.
Purpose of sleep
The official term is Synaptic Homeostasis.
Any information the brain records during the day is called synaptic potentiation. This happens when we are awake.
If we record lots of stuff we will have more slow brainwave activity when we sleep.
These are Delta waves (0.5 to 3MHz).
During Delta sleep states synaptic depression occurs.
The stuff our brain does not need is discarded.
Homeostasis, or a stable equilibrium in the brain, is restored. The synaptic connections between the brain cells are regulated at manageable levels.
This is called synaptic downscaling.
What is left is important and becomes our memories.