sleep cycle

• ultradium rhythm is more than once in 24 hours
• frequemcy - how close waves are
• amplitude - size of waves
• wave types - delta - theta - alpha - beta
• theta and delta distinguish the sleep stages
• 4 stages of sleep
• 1 -3 are NREM sleep
• 3 stages - N1 - N2 - N3
• stage 4 is REM
• REM - rapid eye movement
• most dreams are in rem
• one cycle is 90 mins
• 4-5 cycles in one sleep
• sleep becomes deeper from N1 to N3 - less easily woken - slowing of brain frequency - increased amplitude
• N1 - light sleep - easy to wake body may move suddenly - sensation of falling - mild halucinations
• n1 - eeg shows theta waves with slow frequency and high amplitude
• N2 - deeper sleep - harder to wake - body is relaxed - heart rate and temp are lowered
• n2 - eeg shpws theta but also sleep spindles and k complexes
• n3 - deepest sleep - difficult to wake up - most relaxed sleep - lowest heart rate
• n3 - eeg sees slow frequency and large amplitude delta waves
• REM - returns to active brain state - similar to wakefullness
• REM - eeg body is paralysed - when woken report vivid dreams
• brain returns to N1 after REM
• each cycle has a larger REM and shorter duration of N3
• Dermot and Kleitman - eeg recordings of participants sleep - brain waves followed a pattern of activation - relaxation in slow wave and activation in REM
• shapiro - ultramarathon runners showed longer sleep after intense activity - increase proportion of slow wave sleep - suggests N3 needed for physical recovery
• Haider - eeg of 10 patients recovering from overdose - increased rem - rem is for mental recovery
• pros of sleep research - more sophisticated eegs - development of technology
• brac cycle - basic rest activity cycle
• brac - kleitman
• brac - cycle we go through in 90 mins in the day - altert to sleepy - explains why work is broken up with coffee breaks
• brac app - musicians and atheltes - break up practise into 90 mins for maximum efficiency
• brac - ultradium rythms