Ultradian Rhythms

• Ultradian Rhythm

  biological process that repeats more frequently than once every 24 hours. (eg minutes/hours)
• How is the sleep cycle ultradian rhythm’s studied?

  Electroencephalogram, showing brainwave features such as frequency, How close the waves are to each other (waves per second in Hz) and amplitude, the size of the brain wave (change in voltage). Five distinctive brainwave patterns are delta, theta, alpha, beta and gamma. Theta and Delta distinguish sleep stages.
• Outline N1 of sleep

  Light sleep. Easy to wake, body may move suddenly (hypnic jerks). sensation of falling, mild auditory or visual hallucinations (hypnagogic hallucinations). Theta waves
• Outline N2 of sleep

  Deeper Sleep. Harder to wake, the body is relaxed, heart rate and body temperature are lowered, and the eyes are still. Theta, but sleep spindles and K complexes.
• Outline N3 of sleep

  Deepest Sleep - Very difficult to wake, body at its most relaxed with heart-rate at its lowest. delta waves (slow wave sleep).
• Outline REM of sleep

  Brain returns to active state similar to wakefulness (EEG) passing back through N2 and N1, body is paralysed, Rapid Eye Movement and dreaming
• Describe how Dermot and Kleitman (1957) studied the sleep Ultradian Rhythm


  Study 1: EEG recordings made of 33 participants over a nights sleep. Brain waves followed a cyclic pattern of activation, with bodily relaxion occurring during slow wave sleep and rapid eye movement during periods of high activation.

  Study 2: 9 participants woken at different stages in their sleep cycle reported dreaming in the REM
• Describe how Shapiro (1981) studied the sleep Ultradian Rhythm

  Ultramarathon runners showed longer sleep after intense physical activity. Also an increased proportion in slow wave sleep, suggesting SWS (N3) is for physical recovery of the body. EEG of 10 patients recovering from drug overdose showed increased REM sleep, suggesting REM is for mental recovery
• How has psychological research been used to improve peoples sleep cycle ultradian Rhythm

  Technology and devices based on understanding sleep stages have been developed. These track sleep and help individuals improve sleep. Avoiding waking in stage 4 stops people feeling groggy and disoriented. This technology leads to happier, healthier and more economically productive population.