5 - sleep Flashcards
Why do we need sleep in terms of physical well-being?
- For immune function, cardiovascular health, metabolic health, and physical performance recovery
→ Immune function: during sleep, the body produces sidocains, which are proteins that help prevent infection, and sleep disturbance messes with the immune system which makes it difficult to fight colds p.ex
→ Cardiovascular: sleep regulates the heart and gives the heart a chance to rest by reducing blood pressure
→ Metabolic health: sleep is associated with overall metabolism and sugar levels
→ Physical performance: there has been research done that shows sleep repairs muscular damage and can help you recover from injuries
Why do we need sleep in terms of mental well-being?
- Cognitive function, emotional regulation, mental health, stress response
- Memory consolidation and cognitive processing occurs during sleep
→ the brain organizes and stores new information during sleep making it easier to recall later
→ Without sleep, we become more emotionally dysregulated
→ a lack of sleep can increase stress due to cortisol - Allows our body to rest and prepare for the next day
Without proper sleep, there can be ___ ___ effects on health; what are these effects?
Detrimental negative;
→ Even one night of sleep deprivation impairs cognition
→ lack of sleep can be chronic or occasional, chronic can lead to physical deficiency
In humans, after total of __ days of sleep deprivation, brain scans can no longer distinguish between someone who is under extreme deprivation and someone who is not.
10 days
→ the scan of the person who was sleep deprived for 10 days looks the same when they’re asleep as when they’re awake, which is an indication that you’re operating at suboptimal level because you’re essentially half-awake and half-sleeping all the time
How is sleep associated with Alzheimer’s?
- Beta amyloid build up (toxic protein) is associated with alzheimers
→ lack of sleep increases this toxic protein in the brain, the more this protein builds up, the greater the risk of developing alzheimers in life
What other conditions are associated with poor sleep?
→ cancer, cardiovascular issues, heart attacks
How many hours of being awake is the same as drinking and driving?
Approximately 19 - 20 hours
What type of brain scan is typically used to study sleep?
EEG
What are the 2 types of sleep? Elaborate on them.
- Rapid-eye-movement (REM) sleep vs non-rapid-eye-movement (NREM) sleep
- On an EEG, REM is identified by its low amplitude, and high frequency
→ amplitude meaning how big the waves are
→ frequency being fast or slow waves - REM is typically related to dreaming; when in REM sleep, your arms and legs are typically paralyzed, which is thought to be a neurological safeguard which essentially prevents us from acting our dreams
Briefly explain the stages of nREM sleep.
3 stages:
- N1, N2, N3 – waves becoming slower from N1 to N3 and eyes remain still
- We cycle through these stages many times throughout the night
→ in healthy adults: N1 (1 - 7 mins); N2 (10 - 25 mins); N3 (20 - 40 mins)
→ following N2, there’s a lighter, non REM 5-10 min period which is typically followed by REM
Explain stage 1 of nREM sleep.
-
Transition State
→ Primarily a transitional phase between wakefulness and deeper sleep
→ marks the period when the body and mind begin to disconnect form the environment
→ typically only lasts a few minutes
→ serves as a gateway for the more restful stages of sleep -
Light Sleep
→ Characterized by light sleep, meaning that the individual is still easily awakened
→ not yet a restorative sleep that occurs in later stages, but allows the body to wind down -
Reduced Brain Wave Activity
→ The brain’s electrical activity begins to slow down
→ transitioning from rapid beta waves, which are associated with wakefulness, to slower alpha and beta waves, which are more associated with sleep
→ brain’s mental activity is starting to decrease -
Slow Eye Movements
→ Indicating that the body is relaxing
Explain stage 2 of nREM sleep.
-
Muscle Relaxation
→ Muscles become more relaxed compared to Stage 1
→ preparing the body for deeper stages of sleep -
Decreased Body Temperature
→ Crucial part of preparing the body for deep sleep
→ helps to slow bodily functions -
Reduced Heart Rate
→ Body’s process of conserving energy -
Sleep Spindles on EEG
→ Sudden bursts of oscillatory brain activity that occur approximately every 10-20 seconds
→ this stage also plays a role in memory consolidation and protecting the brain from external stimuli
→ one of the defining features of stage 2 sleep -
K-Complexes on EEG
→ Large, slow waves that occur in response to external stimuli (p.ex: alarm going off)
→ thought to be a protective mechanism to prevent the sleeper from waking up
→ also play a role in memory
Explain stages 3 & 4 of nREM sleep.
-
High Voltage, Low Frequency Brain Waves
→ known as slow-wave sleep (SWS) or deep sleep
→ Characterized by the presence of high-voltage (amplitude), low-frequency brain waves (i.e., delta waves)
→ delta waves dominate the EEG, indicates there is a significant reduction in brain activity and you are in a deep state of rest -
Restorative Sleep
→ Most restorative phases of sleep
→ The body engages in vital processes such as tissue repair, muscle growth, and the release of growth hormones + memory consolidation and clearing metabolic waste products from the brain
Explain REM sleep.
-
Rapid Eye Movements
→ Movements are quick and sporadic
→ Typically occur beneath closed eyelids, signaling the beginning of REM sleep
→ also associated with visual experiences (dreaming) -
Vivid Dreaming
→ Dreams are more detailed and emotionally charged compared to those in non-REM sleep stages
→ most commonly occurs here, but may also occur during other stages -
Increased Brain Activity
→ Exhibits activity levels similar to or even higher than those during wakefulness
→ fast and low voltages, which is very similar to wakefulness -
Increased Heart Rate
→ Increases in HR which may fluctuate, mimicking the variability seen during wakefulness
→ increase in overall autonomic system during this stage -
Increased Respiratory Rate
→ Increases and becomes more irregular during REM sleep -
Active Inhibition of Voluntary Muscles
→ This paralysis prevents the sleeper from acting out their dreams ensuring the body remains still
→ only breathing and eye movement remain active during this stage
→ this is one of the most distinctive features of REM
→ also known as REMatonia
Define sleep architecture.
- Patterns of sleep cycle and changes throughout the night
→ helps in assessing the quality of sleep and identifying potential sleep disorders
