Ultradian

• Ultradian rhythms last for less than 24 hours
• The stages of sleep - ultradian rhythm - last around 90 minutes and occur 4 - 5 times a night
• stages 1 and 2 of the sleep cycle - slow waves ( alpha and theta ) - light sleep
• stages 3 and 4 are faster waves ( delta waves ) - deep sleep
• Stage 5 - the body is paralysed but activity is high - rapid eye movement sleep
• AO3. There are methodology issues in this researich EEGs were used to understand the sleep cycle.
• AO3. There are individual differences in the sleep cycle. Tucker found that individual lengths of the sleep cycle varied. Specifically, some individuals had a longer REM phase than others. Further research needs to be conducted to understand the reason for this difference
• AO3. There is research support for the sleep stages. Kleitman studied 9 participants who slept in a lab and monitored their sleep cycle using an EEG.