Infradian and Ultradian Rhythms

• Infradian rhythms 


  Last longer than 24 hours and can be weekly, monthly, or annually. An example is the female menstrual cycle
• Ultradian rhythms 


  A frequency of more than one cycle in 24 hours
• Example of Ultradian rhythms 


  Stage 1+2 are the 'light sleep' stages. During these stages, brainwave patterns become slower and more rhythmic, starting alpha and progress to theta waves. Stage 3+4 are 'deep sleep' or slow wave sleep stages, it is difficult to wake someone up. Associated with slower delta waves. Stage 5 is REM (dream) sleep. The body is paralysed and brain activity resembles that of an awake person