Last year, I attended a talk about “sleep” by a world renown sleep expert. I thought the subject was fascinating, especially as I was approaching the sleepless life of being a new parent.
Below for summary.
-Rhythms: Infradian (more than one day), circadian (daily), ultradian (within a rhythm). Sleep sessions are circadian; sleep cycles (REM/NREM) are Ultradian
-Sleep monitoring consists of measurements of EEG (brain waves), EOG (eye movements) and EMB (muscle tension)
-non-REM (NREM) characteristics: low frequency, high amplitude waves
-REM characteristics: high frequency, low amplitude waves; wakeful EEG patterns, low EMG patterns
-Sleep states are defined by combination fo EEG, EOG, EMG in 30 second epochs
-Over the course of a normal sleep night: early portion of the night, deeper NREM, shorter REM; later portion of the night, shorter NREM, longer REM
-Why you can’t remember dreams: if you wake up during NREM, you won’t remember
-Takes 4 mins to develop memory—wake events shorter than 4 minutes may not leave memory impact
-Children have longer deep sleep states, lessens as you get older
-“Sleep like a baby” = deep NREM, more REM cycles, less awake events, sleep longer (as you age, all these go down)
-Why we sleep: homeostatic sleep drive + circadian sleep drive.
-homeostatic = length of sustained wakefulness; circadian = set by light and environmental factors
-early portion of night, we pay off sleep debt, and circadian drive keeps sleep going. Circadian drive = more REM
-jet lag = hard to sustain full sleep b/c circadian rhythm doesn’t keep sleep going, so you’re just paying off sleep debt
-You can’t pay off sleep debt in one night; you pay off some sleep debt each night; circadian sleep won’t let you pay it off all at once
-takes about 4-5 days of one night of bad sleep
-progressive deterioration = consecutive nights of bad sleep accumulates. One night of bad sleep doesn’t affect next day, but may affect days after; likewise, optimal performance is about multiple nights of sleep, not just night before
-sleep latency (amount of time it takes you to fall asleep) is generally proportional to your sleep debt. Quicker you fall asleep the more sleep debt you have
-screens: light info detected by retna goes to hypothalamic nucleus, which set circadian rhythm. So certain light triggers can mess with circadian rhythm
-west bound travel easier b/c light exposure prolongs circadian rhythm
-normal human circadian clock is around 25.3 hours (~25-26 hours). Environmental factors keep us at 24 hours (exposure to sunlight, temperature, etc.).
-Arousal/Environmental factors impact and contribute to sleep disruption
Book Summaries. Less than 272 words. 