Sleep and Hormones Lecture Notes

Importance of Hormones in Sleep

• Melatonin: Known as the nighttime hormone that induces sleepiness.
• Growth Hormone Release:
  • Occurs both day and night.
  • Major release (bolus) during the first sleep cycle, especially during deep slow-wave sleep.
  • Missing the first deep slow-wave sleep reduces the initial big bolus of growth hormone.
  • Big boluses have different effects than gradual release.
  • Important for protein synthesis and memory building, especially after learning.

Impact of Missing First Sleep Cycle

• Sleeping later than usual (e.g., starting sleep at midnight instead of 10 PM) can lead to missing the first sleep cycle and its hormonal benefits.
• Body works on a synchronized circadian clock, making it important to maintain consistent sleep schedules.
• Growth hormone is released in synchronization with circadian rhythms. Missing this timing can result in inadequate hormone response.

Consistent Sleep Schedule

• Essential for good neurological health, especially as one ages.
• Consistent bedtimes and wake times are crucial.

Sleep Requirements by Age

• Adolescents and teenagers may require more sleep due to brain and body development.
• Important to allow teenagers to sleep more as it supports developmental needs.
• Sleep deprivation can impact developmental clocks and growth.

Inhibitors of Effective Sleep

• Alcohol:
  • Suppresses REM sleep and stage 2 sleep transition.
  • Affects sleep spindles which are important for memory consolidation.
  • Should avoid alcohol 4-6 hours before sleep.
• Caffeine and other lifestyle factors also play a role but were not detailed in this session.

Stages of Sleep

• First Sleep Stage:
  • Focus on growth hormone release and initial deep sleep benefits.
  • Important for early memory and learning consolidation.
• Second and Third Sleep Cycles:
  • Increased REM sleep.
  • Hormonal changes; decline in growth hormone and melatonin, increase in other hormones.
  • Important for creativity and schema building.

Conclusion

• Maintain a regular sleep schedule for optimal hormonal and cognitive benefits.
• Ensure sleep environment and pre-sleep activities support the natural sleep cycle.