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What Happens to us while we sleep?

Sleep Science Portal   /  What Happens to Us While We Sleep?

Our brains and bodies coordinate their activities to promote better sleep. The facts are fascinating.

First, the brain signals the body to get ready for sleep.

  • Melatonin released in correct light environment to initiate the sleep process.
  • Heart slows down, skin temperature rises, core body temperature cools.
  • Human growth hormone released during first part of the night during deep sleep aiding physiological recovery.
  • Heart rate and blood pressure dip, giving the cardiovascular system a rest.
  • Second half of the night, rapid eye movement (REM) is dominant, taking care of the brain: emotional stability, memory function, creativity and problem solving.

There are four main stages of sleep, each playing a vital role. We go through 4-6 cycles of these stages per night consisting of various percentages of each stage:

Stage N1: Light sleep: ~5% of the night. This is our transition from wake to sleep.
Stage N2: Moderately deeper sleep: ~50% of the night. Memory protection, psychomotor enhancement.
Stage N3: Deep, slow wave sleep: ~20% of the night. Memory processing, human growth hormone secretion, physiological recovery/maintenance.
Stage REM: Rapid eye movement: ~20% of the night. Cognitive, emotional maintenance. Neurological health.
Awaking: Time in bed after sleep.

WHAT ARE THE BENEFITS OF QUALITY SLEEP, AND WHAT ARE THE RISKS IF YOU ARE NOT GETTING ENOUGH?

BENEFITS

  • Immune function (common cold, vaccination effectiveness against viruses, resistance to diseases)
  • Weight management — quality sleep regulates our appetite system along with blood sugars, cholesterol, triglycines, insulin (diabetes precursors)
  • Cardiovascular health (HRV, blood pressure)
  • Moderates pain — poor sleep lowers our pain threshold
  • Recovery from exercise, injuries and illnesses

RISKS

  • Excessive Daytime Sleepiness (Research Study in partnership with Mayo Clinic)
  • Cognitive deficiencies (memory, emotional, mental health and wellness, brain health)
  • Safety (drowsy driving, workplace accidents)

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