Ultradian and Infradian rhythms

Question 1

Define infradian rhythms?

Answer 1

Biological cycles that last longer than a day 24hrs

Question 2

Examples of infradian rhythms

Answer 2

E.g migration patterns, flowering, menstrual cycle, SAD

Question 3

Define ultradian rhythms

Answer 3

Biological cycles span a period less than one day.

Question 4

Ultradian rhythm examples

Answer 4

E.g sleep/wake cycle

Question 5

Examples of infraradian weekly rhythms

Answer 5

• Lower testosterone levels peak at weekend
• Lower frequency of births at the weekend

Question 6

What dictates the menstrual cycle?

Answer 6

Dictated by the SCN and endocrine system (pituitary gland releases FSH/LH to stimulate ovulation)

Question 7

Menstrual cycle

Answer 7

• Dictated by the SCN and endocrine system (pituitary gland releases FSH/LH to stimulate ovulation)
• Ovulation occurs halfway through the cycle when oestrogen levels peak
• After ovulation, progesterone levels ^ to prepare implantation of embryo in the uterus

Question 8

How long is menstrual cycle on average?

Answer 8

Cycle is reported 28 days on average

Question 9

What does refinetti report on infradian rhythm

Answer 9

(Refinetti reports 23-36 days)

Question 10

What is an annual rhythm example

Answer 10

Annual rhythm example SAD ( seasonal affective disorder)

Question 11

Seasonal affective disorder explanation

Answer 11

Research suggests seasonal mood variation in humans
* Some people become more depressed in winter months

• Winter months → lack of light results in longer melatonin secretion affecting serotonin
  During the winter more heart attacks occur and more deaths occur in january

Question 12

Russel study

Answer 12

Russel - daily sweat samples collected and rubbed onto upper lips of other women’s - cycles came synchronised by ‘odur donut’
Suggesting synchronisation can be affected by pheromones that have an effect on people close by rather than the individual producing them

Question 13

whats an example of the ultradian rhythm?

Answer 13

sleep cycle

Question 14

What does REM and NREM mean?

Answer 14

REM - rapid eye movement
NREM - non-rapid eye movement

Question 15

how long is the sleep cycle on average?

Answer 15

The human sleep stage 1-4 involves a 90-100 minutes of REM (rapid eye movement) and NREM (non-rapid eye movement) sleep.

Question 16

What can be used to monitor sleep cycles?

Answer 16

EEGs can be used to monitor these patterns

Question 17

How many stages in the sleep cycle are there?

Answer 17

5 stages

Question 18

stage one

Answer 18

Light sleep&raquo_space;
Muscle activity slows down

Question 19

Stage 2

Answer 19

Breathing and HR slows

Question 20

Stage 3

Answer 20

Deep sleep begins&raquo_space;>
Begins to generate slow delta waves

Question 21

Stage 4

Answer 21

Very deep sleep&raquo_space;
* Rhythmic breathing
* Limited muscle activity
* Brain produces delta waves

Question 22

stage 5

Answer 22

REM»
* Brainwaves speed up
* Dreaming occurs

Question 23

Who determined BRAC cycle?

Answer 23

Kleitman

Question 24

What does kleitman mean by the BRAC cycle

Answer 24

suggests this 90 minute cycle actually happens all day

• Difference is during the day rather than moving through sleep stages we move through stages of alertness into stage of hunger/fatigue every 90 minutes
  **
  Suggests this is evident in people’s mid morning coffee at 10:30 which breaks the morning into 90 min intervals from 9-noon**

Question 25

Case study - Tripp

Answer 25

• stayed awake for 8.5 days for charity
  Experienced mood swings, body temp drop, hallucinations, paranoia → if cycle is disrupted can have serious consequences

Question 26

Gardener - case study

Answer 26

stayed awake for 11 days
Suffered little symptoms of nausea but later experienced suffer extreme insomnia

Question 27

Strengths - rhythms

Answer 27

• Research support for BRAC - UR
  Ericsson studied a group of elite violinists → found the practice sessions were no more 90 mins at a time, and place systematically throughout the day , included with naps

The more able, the more naps

Consistent with the claim of 90 minute fatigue, providing real world application

Additionally, was found within musicians, athletes ,chess and writers → more generalizable

Question 28

Limitations

Answer 28

• Individual differences in sleep - UR
  Usually attributed to differences in non biological factors (EZS)

HOWEVER, Tucker study - sleep in strict Laboratory
Researchers assessed sleep duration, type to fall asleep etc
They found a large ID in each which showed up consistently across 8 nights.

As the environment was tightly controlled means the ID were not driven by circumstance - partial support as is still partly biologically determined

• Menstrual cycle - role of (EZs) RUSSEL et al
  Is usually governed by EPs by release of hormones
  When many women live together not taking oral contraceptives cycles sync
• Study - daily sweat samples collected and rubbed onto upper lips of other women’s - cycles came synchronised by ‘odour donur’
  Suggesting synchronisation can be affected by pheromones that have an effect on people close by rather than the individual producing them
  Hormonal changes can be influenced so cycles can be influenced by external factors.
• Belief in lunar rhythms - alternative
  The belief in infradian rhythms based on the moon is still prevalent.
  Midwives still believe more babies are born during full moon than a new moon
  Erlis - surveys of workers in the mental health profession showed persistence in views the full moon can alter behaviour even after studies proved otherwise.
• Validity and reliability of sleep patterns
  Lab environment → modifying the research
  Biologically or non-biological factors (temp,sleep hygiene)

Sleep patterns are biologically deterministic/reductionist saying all sleep the same cycles
as (temp,sleep hygiene) external factors contributed

Question 29

sleep deprivation study how to evaluate them

Answer 29

• TRIPP → stayed awake for 8.5 days for charity → got hallucinations / Paranoia
• Garderner → teenager stayed awake for 11 days → only nausea but later life extreme insomnia

Studies both lend support to the idea sleep is vital for maintaining physical and mental health. However, highlight the effects of deprivation and sleep cycles may vary between individuals as the symptoms suffered where not identical

Question 30

Explain the difference between infradian rhythms and ultradian rhythms - 2 marks

Answer 30

The difference between an infradian and ultradian rhythm is the duration of the cycle. An infradian rhythm is one that lasts longer than 24 hours whereas an ultradian rhythm lasts less than 24 hours.