ultradian and infradian rhythms Flashcards
infradian rhythms
biological rhythms that take longer than 24 hours to complete full cycle
ultradian rhythms
biological rhythms that last under 24 hours
2 topics in ultradian rhythms
sleep cycle
basic rest activity cycle (brac)
sleep cycle
one fulll cycle = 90 min
5 distinct stages of sleep
cycle repeats itself loads per night
What happens during Stage 1 of sleep?
Light sleep, muscle activity slows, and it’s easy to be woken. Alpha waves are present.
Stage 2 of sleep
slightly deeper sleep, breathing and heart rate slow. Theta waves are present.
stage 3 of sleep
Deep sleep begins, it’s harder to wake someone, and slow delta waves start appearing.
stage 4 of sleep
Very deep sleep, it’s difficult to wake someone, and the brain produces delta waves. Rhythmic breathing occurs with limited muscle activity.
stage 5 of sleep
Rapid eye movement occurs, dreaming happens, brainwaves speed up, the heart rate increases, breathing is rapid and shallow, and the body is paralyzed.
kleitman 1969
He suggested that a 90-minute cycle of alertness followed by fatigue continues throughout waking hours.
what was the key finding from Ericsson et al. (1993) regarding BRAC in violinists?
The best performers practiced in 90-minute sessions with breaks in between to recharge.
ao3 strength ultradian
p- supporting research that suggests there’s qualitivately different stages in sleep
e- dement and kleitman investigated when dreaming occurs in sleep, monitored EEG records and found that participants woken during REM sleep reported dreams 80-90% of the time.
E – REM activity during sleep correlated with dreaming, brain activity varied
according to how vivid dreams were.
L – The study suggests that REM sleep is a distinct ultradian rhythm and an
important component of the ultradian sleep cycle.
ao3 strength ultradian
P – Research support for the BRAC comes from studies of elite performers.
E – Ericsson (2006) found elite violinists practice sessions were usually limited
to a duration of no more than 90 minutes, with practice distributed during the day
into 90 minute segments.
E – His research also indicated that violinists frequently napped to recover from
practice and he discovered the same pattern among other musicians, athletes,
chess players and writers.
L – This supports the existence of a 90 minute ultradian cycle of alertness and
fatigue.
2 topics in infradian rhythms
- menstrual cycle
- seasonal affective disorder
menstrual cycle
-influenced by monthly changes in hormone levels
-which regulate ovulation
- average length of cycle - 28 days
- between 24-35 days = normal
how many hormones regulate the cycle
4
all 4 hormones and their functions
fsh - causes the egg to mature
lh- causes eg to be released
oestrogen, inhibits the production of fish, and encourages production of lh, to ensure only 1 egg matures each month
progesterone , causes te lining of the uterus to thicken in preparation for a fertilised egg to be implanted
Stern and McClintock’s
- studied 29 woman with irregular menstrual periods participated in the study
- samples of pheromones were taken from 9 woman, at diff stages of menstrual cycle
- samples were treated w alc and frozen
- to be rubbed on upper lip of 20 other ppts
- on day 1 , pads from the start of menstrual cycle were applied to all 20 woman, and etc
- found that 68% of women experienced changes to their menstrual cycles brought them close to the cycle of their ‘odour donor’
- provides that endogenous menstrual cycle can be influenced by exogenous facts ( cycles of other woman)
seasonal affective disorder
- Mental disorder causing depression in winter, with recovery in summer.
- Shorter daylight hours and longer nights in winter affect hormone levels.
-Lower levels of serotonin (the “happy” neurotransmitter) are linked to depression.
- increased melatonin levels during winter due to longer darkness, which induces sleep.
Darkness triggers melatonin production.
P – There is research support for the existence of an infradian rhythm for the menstrual cycle.
E – Stern & McClintock studied 29 women with irregular periods. Samples of pheromones
were gathered from 9 of the women at different stages of their menstrual cycles. The samples
were treated with alcohol and frozen, to be rubbed onto the upper lip of the other 20
participants.
E – They found that 68% of women experienced changes to their menstrual cycle which
brought them close to the cycle of their ‘odour donor.’
L – This provides evidence that there is an infradian rhythm for the menstrual cycle, and it can
be influenced by exogenous factors (the cycles of other women).
ao3 infradian
Infradian – Methodological issues
P – However, the methods used in these early synchronisation studies can be criticised for
having too many confounding variables
E – For example, stress, diet, exercise and many more factors can all influence a woman’s
menstrual cycle, meaning the findings of studies like McClintock’s could be less valid than
first thought.
E – Moreover, research in this area tends to use small sample sizes and relies on self-report
data from participants, further questioning the validity and generalisability of results.
L – This suggests that findings from early research into the menstrual cycle should be taken
with caution as they may be less valid than previously thought.
