Biopsychology- Bio Rhythms: Infradian And Ultradian Rhythms Flashcards
Infradian rhythm -
A type of biological rhythm with a frequency of less than one cycle in 24 hours, such as menstruation and seasonal affective disorder.
Ultradian rhythm -
A type of biological rhythm with a frequency of more that one cycle in 24 hours, such as the stages of sleep.
What are biological rhythms?
Biological rhythms are cycles in living organisms (plants, animals, and humans) that influence body systems. They are controlled by endogenous pacemakers (internal biological clocks) and exogenous zeitgebers (external environmental cues).
What are the different types of biological rhythms?
The three types of biological rhythms are:
Ultradian rhythms (occur multiple times within a day).
Infradian rhythms (take longer than a day to complete).
Circannual rhythms (last for about a year).
What is a circadian rhythm?
Circadian rhythms are biological rhythms that last around 24 hours, such as the sleep/wake cycle and core body temperature, derived from the Latin words “circa” (about) and “diem” (day).
What is the role of exogenous zeitgebers in circadian rhythms?
Exogenous zeitgebers, like light and meal times, influence biological rhythms. For example, daylight is a key zeitgeber for the sleep/wake cycle, helping regulate when we feel drowsy or alert.
What would happen if the body was left without external cues?
If there were no external cues like light, the biological clock would continue running but would likely extend beyond 24 hours, leading to a “free-running” rhythm that is not aligned with the 24-hour day.
What did Siffre’s cave study demonstrate?
Michel Siffre’s cave study showed that, without natural light, his biological rhythm extended to around 25 hours. However, he still maintained a regular sleep/wake schedule even though his perception of time was distorted.
What did the Aschoff and Wever bunker study reveal?
Aschoff and Wever’s study conducted in a WWII bunker found that most participants’ sleep/wake cycles lasted between 24 and 25 hours without natural light. This suggested that the internal biological clock might be slightly longer than 24 hours but is influenced by external cues.
How did the Folkard et al. (1985) study contribute to our understanding of circadian rhythms?
Folkard et al. found that when participants were exposed to a 22-hour day (with the clock sped up), only one participant adapted, showing that the biological rhythm is strong and difficult to override by external cues.
What practical applications does the research on circadian rhythms have for shift work?
Circadian rhythm research has highlighted that shift work disrupts the sleep/wake cycle, leading to reduced concentration, a circadian trough (period of reduced alertness), and an increased likelihood of mistakes and accidents. It also links shift work to poor health outcomes, including heart disease.
How does circadian rhythm research inform drug treatments?
Circadian rhythms affect how drugs are absorbed and distributed in the body. Research has led to the development of guidelines on the timing of drug administration for various conditions (such as cardiovascular and anti-cancer treatments) to ensure maximum effectiveness.
What is a limitation of using case studies in circadian rhythm research?
Case studies often involve small, unrepresentative sample sizes, which can limit the ability to generalize findings to a larger population. For instance, Siffre’s results at age 60 may not reflect the circadian rhythms of younger people or the general public.
How does the use of artificial light complicate circadian rhythm research?
Some studies, like Siffre’s, used artificial light during the study, which was assumed not to affect the biological rhythm. However, later research (e.g., by Czeisler et al. in 1999) demonstrated that even dim artificial light can shift circadian rhythms, making it a potential confounding variable.
Why are individual differences a challenge in circadian rhythm research?
Individual differences complicate the generalization of findings because circadian rhythms can vary widely from person to person (ranging from 13 to 65 hours). Additionally, some people are “larks” (early risers) while others are “owls” (night owls), and age can also influence sleep/wake patterns.
How do individual differences, like being a “lark” or “owl,” affect sleep/wake patterns?
Some individuals naturally prefer going to bed early and waking up early (“larks”), while others prefer staying up late and waking up later (“owls”). These differences complicate the research into circadian rhythms, as results may not apply universally.
What impact does age have on circadian rhythms?
Research shows that sleep/wake patterns can change with age. For example, older individuals may have different circadian rhythms than younger people, affecting their sleep patterns and general biological rhythms.
What was the main finding of Siffre’s 1999 cave experience?
In his 1999 cave study, Siffre found that, at the age of 60, his internal clock ticked more slowly than when he was younger. This illustrates that even for the same individual, circadian rhythms can change with age.
How does shift work affect health according to circadian rhythm research?
Shift workers, especially those who work night shifts, are at an increased risk for health issues, including heart disease, possibly due to disrupted sleep patterns and poor-quality sleep during the day.
What was the purpose of the Folkard et al. study on speeding up the clock?
The study by Folkard et al. aimed to test how easily participants could adjust their circadian rhythms when exposed to a shortened 22-hour day. Most participants could not adapt, indicating the strength of the free-running circadian rhythm.
What is “desynchronization” in the context of circadian rhythms?
Desynchronization refers to the disruption of the biological clock caused by irregular sleep/wake cycles, such as those experienced by shift workers. This misalignment can lead to health issues and cognitive impairments.
