2Why sleep ? Brain development Memory / cognition / long term potential ImmunityConservation energyRepair & Restoration
3Sleep hygiene Regular sleep time Proper sleep environment Stimulation controlAvoidance of time in bed worryingAvoidance of poorly timed alcohol and caffeineRegular exercise but not within 3 hours of bedtimeWind-down timeLate-night high-tryptophan snack
4Circadian clockHuman circadian clock generates a rhythm slightly longer than 24 hours when it has no external cue to set it.Most people can adjust to 23- or 25- hour day but not to a 22- or 28- hour day.Bright light late in the day can lengthen the circadian rhythm.
5Duration of sleep Circadian rhythm Circadian clock Zeitgeber Circannual rhythmThe purpose of the circadian rhythm is to keep our internal workings in phase with the outside world.Light is critical for periodically resetting our circadian rhythms.A zeitgeber is a term used to describe any stimulus that resets the circadian rhythms.Exercise, noise, meals, and temperature are others zeitgebers.
16Benefit of meditationMeditation = practices that train attention to heighten awareness and bring mental processes under greater voluntary controlYoga, Zen, transcendental meditation (TM)Potential physiological benefitsSimilar to effective relaxation procedures
24Sleep stage II : NREM II Sleep spindles K complexes Vertex waves Brief , 12 – 16 Hz , synchronous bursts of activity , usually maximal in the central , or less commonly frontal , regionsK complexesOften accompany sleep spindles . A sharp negative wave followed by a high-voltage slower waveVertex wavesNamed for tendency to phase reverse in central regions.Sharp wavesMay occur in trainsK complexs & Vertex waves may result from brief sleep disturbances
25NREM2 sleepEEG: - sleep spindles (oscillating with the frequency between Hz)- K-complexes (high voltage, sharp rising and sharp falling wave)- relatively low voltage mixed frequencyEOG: - the absence eye movementsEMG: - constant tonic activity
26Sleep stage III : NREM III > 20 % but < 50 % of the background rhythm is Delta activity
27NREM3 sleep EEG: - consists of high-voltage (>=75uV) - slow delta activity (<=2 Hz) // electrodes Fpz-Cz or Pz-OzEOG: - the absence eye movement- delta waves from EEGEMG: - low tonic activities
28Sleep stage IV : NREM IV> 50% of the background rhythm is Delta activity
29REM sleep Bursts of rapid eye movement Loss of muscle activity “ Desynchronization ” of the background rhythm.The predominant delta rhythm of slow wave ( stage III & IV ) sleep is replaced by faster frequency ( beta and theta ) rhythms normally seen during the wakeful state.Sawtooth waves