What is Restorative Sleep?

This SleepSomatics blog article is part two of a four part series on sleep quality, sleep disorders, sleep & weight loss, and in-lab sleep study testing.

Part One: What is the Sleep Architecture

Part Two: What is Restorative Sleep

Part Three: What Causes Deficient Restorative Sleep

Part Four: Restorative Sleep and Weight Loss

This video is about the five myths of restorative sleep, symptoms and causes of poor or reduced restorative sleep, how to fix broken restorative sleep, how restorative sleep is measured, and the differences between a sleep study (or polysomnogram) and home sleep test (or home sleep study) for quantifying and treating restorative sleep loss to improve symptoms of fatigue, moodiness, insomnia irritability, difficulty concentrating, low libido, depression, and increase weight loss and energy.

What is Restorative Sleep

In Part One: What is the Sleep Architecture, we discussed how we spend one-third of our lives asleep. 121 days annually and 9,581 days in our lifetime are spent sleeping. Despite the critical importance of sleep on our health and quality of life, insufficient or inadequate sleep is an epidemic in United States, with one-third of Americans being sleep deprived or suffering from an undiagnosed or untreated sleep disorder or sleep problem.

Sleep is a neurologically dynamic environment where the brain is progressing through alternating cycles of light and deep sleep (or sleep stages) known as the sleep architecture. These alternating sleep stages allow the brain and body to physically and cognitively restore itself. Polysomnography (or an in-lab sleep study) evaluates a patient's actual sleep architecture, quantifying their specific indices of these sleep stages (or restorative sleep).

Sleep Deprivation Effects

Sleep deprivation (and the resulting deficient restorative sleep) often explains a patient's daytime symptoms. However, even in patients who sleep 7-8 hours nightly may still be deprived of sufficient restorative sleep (such as patient's with undiagnosed sleep-disordered breathing or sleep apnea and restless leg syndrome). When restorative sleep is deficient, symptoms include:

  • ADHD, Anxiety, Depression, and Mood Swings
  • Car accidents, worsened reaction time when driving
  • Cognitive impairment, mental fogginess, forgetfulness
  • Daytime somnolence (or excessive sleepiness)
  • Fatigue or lack of energy
  • Lower testosterone, lowered libido, impotence
  • Reduced immune system (always getting colds, flu)
  • Sleep deprivation or reduced quality sleep
  • Type 2 Diabetes (or increased blood glucose levels)
  • Weight Gain or Obesity

related: order your home sleep apnea test & consultation today


If you don't feel refreshed or alert when you wake up, or if you feel groggy or irritable during the day, the underlying reason (or a contributing factor) likely will be identified in your indices of restorative sleep.

Sleep Stages, Types of Sleep, and the Sleep Architecture

There are four sleep stages identified by the American Academy of Sleep Medicine (each listed below with their alternate names) which are grouped by their classification as "non-REM" (NREM) and "REM":

  • Stage 1 (Stage NREM1 or Stage N1)
  • Stage 2 (Stage NREM2 or Stage N2)
  • Stage 3 (Stage N3, delta sleep, slow-wave sleep, SWS)
  • Stage REM (rapid eye movement sleep)

Each sleep stage is categorized by neurological activity:

  • Stage 1 features alpha waves and is the period of light sleep, wakefulness, and muscle tone when a person is first falling asleep.
  • Stage 2 features theta waves and transitions between wakefulness and deeper sleep.
  • Stage 3 Restorative Sleep features delta waves and is associated with stabilized glucose levels, testosterone, human growth hormone, and overall physical bodily restoration.
  • Stage REM Restorative Sleep features rapid eye movement and rapid low-voltage EEG similar to when a person is awake. This is when a person dreams and is associated with cellular regeneration, cognitive restoration, memory allocation, and memory retention.

Adult humans generally progress through sleep cycles every 120 minutes in the following pattern, with more Stage N3 delta sleep found earlier in the evening and more Stage REM sleep found in the later morning hours.

Stage N1 -> Stage N2 -> Stage N3 -> Stage N2 -> Stage REM -> Repeat


The Importance of Restorative Sleep and Sleep Continuity

For adult humans, restorative sleep should account for 50% of the total night's sleep, evenly divided between Stage N3 delta and Stage REM sleep at 20-25% each. Patients usually don't know they are deprived of restorative sleep; rather, they're tired, fatigued, moody, or just don't feel healthy, rested, or well. Perception of total time slept and quality of sleep is often wrong, causing patients deficient in restorative sleep to go untested because they think they got sufficient sleep. This is particularly true in sleep apnea patients who have quantitatively poor restorative sleep. Once we use CPAP to treat the sleep apnea at SleepSomatics, restorative sleep rebounds and daytime sleepiness resolves.

Very often, when a patient seeks testing or treatment at an accredited Austin sleep lab like SleepSomatics, they have symptoms of poor or reduced restorative sleep like sleepiness, fatigue, and reduced quality of life. These reduced restorative sleep patients have often already had their blood levels checked for low testosterone or estrogen, low thyroid, low human growth hormone, poor iron, low vitamin D, low magnesium, etc. These patients often have already been prescribed anti-depressant medications, stimulants, sedatives, and other medications to treat their sleepiness, fatigue, depression, or impotence. And yet none of the prescriptions have worked, causing their doctor to refer them to a sleep lab Austin like SleepSomatics for sleep testing.


Quantifying and Evaluating Sleep Quality

Evaluating the sleep architecture and quantifying restorative sleep indices to determine if a patient is getting their 50% restorative sleep requires an in-lab sleep study. We recommend choosing a credentialed, accredited Austin sleep center or Austin sleep lab like SleepSomatics to confirm your restorative sleep is accurately quantified. Evaluative protocols are set forth by the American Academy of Sleep Medicine (AASM), and an AASM-accredited sleep center or sleep lab Austin like SleepSomatics is required to perform those rigorous sleep medicine and testing processes. Don't trust a smart phone app to diagnose a tumor. Don't trust a smart phone app to diagnose a sleep disorder.

An in-lab sleep study evaluates 70+ sleep disorders, quantifying the sleep architecture and restorative sleep indices and also screening for sleep disorders and sleep disturbances that are causing the restorative sleep deficiency. In Part Three of this SleepSomatics three part series on sleep quality, sleep disorders, and in-lab sleep study testing, we will look at the causes of restorative sleep deprivation and broken sleep, including sleep-disordered breathing (sleep apnea), restless leg syndrome, and anti-depressant medication (SSRI and benzodiazepine) usage.

Concerned you aren't getting enough sleep? If you or someone you care about snores or is tired and fatigued during the day, sleep-disordered breathing (and sleep apnea) may be a serious risk. Get your sleep tested today by SleepSomatics, a professionally credentialed and accredited sleep test center located in Austin since 1999. Call 512.323.9253.


SleepSomatics Diagnostic Center is a credentialed and accredited sleep center serving Austin and Central Texas since 1999. We provide sleep diagnostic and therapy services including In-Lab Sleep Study, Take-Home Sleep Test, and Sleep Therapy. We gladly accept most insurances and provide you with a written quote of any costs. Questions? Get answers. Let's talk. Call us. We're ready when you are. Call SleepSomatics at (512) 323-9253.