Ultradian And Infradian Flashcards
(9 cards)
Infradian rhythms
Rhythms that have a duration OVER 24 hours and may be weekly, monthly or annually. E.g menstrual cycle
Menstrual cycle (infradian)
A woman’s reproductive cycle lasts about a month on average (28 days). It is regulated by hormones that promote ovulation which occurs usually half way through the menstrual cycle when oestrogen levels peak (lasts around 24 hours). After this, progesterone levels increase in preparation for possible embryo implantation in the uterus.
Seasonal affective disorder (infradian)
Seasonal variations in mood, during the winter months where there are longer levels of darkness, our melatonin increases which can decrease our serotonin levels in these periods, leading to temporary depressive spells.
Infradian AO3
+ Russell- rubbed under arm sweat from a sample of one group of women on the upper lip of a second group of women who were kept separated. For 68%, their menstrual cycles became synced (exogenous cues can control the menstrual cycle) - pheromones can impact people.
- However, not 100%!!
+ it was believed that there was an evolutionary reason for synchronising of periods to allow women living together to share child-caring duties. This increases survival chances.
+ RWA- understanding of SAD has lead to treatments such as light therapy which was shown to be effective in symptom reduction in 80% of cases.
+ RWA - understanding of the menstrual cycle has allowed development of treatments such as the pill that target certain hormones to reduce menstrual symptoms as well as knowing what hormone to target to reduce or increase chances of pregnancy in fertility treatments, as well as how hormones can impact mood at different stages of the menstrual cycle.
Ultradian rhythms
A cycle that lasts less than 24 hours such as the cycle of sleep stages that occur throughout the night.
The sleep-wake cycle (ultradian)
- measured through EEGs and each cycle is roughly 90-100 minutes in length.
(NREM stage 1-4)
Stage 1- light sleep, slight muscle activity
Stage 2- breathing and heart rate slows
Stage 3- deep sleep begins
Stage 4- very deep sleep, limited muscle activity.
Stage 5- rapid eye movement, brain activity similar to when we are awake. Dreams and so muscle paralysis occurs to stop activity when dreaming.
Basic rest activity cycle (ultradian)
- 90-100 cycles occur during the awake period. We progress from a state of physiological alterness to fatigue. We can only work for 90 minute blocks before losing concentration.
Endogenous and exogenous pacemakers work together to keep you in time.
AO3 - ultradian - part 1
+ understanding of the sleep wake cycle has practical value as it has allowed us to determine optimum amount of sleep (around 8 hours) to ensure we progress through the sleep stages fully, which improves mood. HOWEVER, individual differences occur which could be due to genetics and different needs/speeds of sleep stages. ALSO, research has found that women need on average slightly more sleep than men as they have greater cross hemisphere connections, leading to a greater multi-tasking and therefore an increased need for sleep.
+ RWA- our understanding of hormones and stages involved with sleep has helped with the development of sleep treatments such as sleeping pills.
+ Ericsson found that elite violinists limited their practice to no more than 90 mins at a time and napped frequently to recover from practice sessions. Common among chess players, athletes, writers etc.
AO3 ultradian - part 2
- artificial lab experiments that measure stages of sleep with electrodes attached to their head are not representative of true, natural sleep environments as anxiety levels will likely be higher due to being watched which can lead to abnormal disruptions to sleep.
RWA- study periods being no more than 90 minutes as well as school periods.
