...Describe and evaluate research into circadian rhythms (8+16) Research into circadian rhythms has assessed the effects of isolating participants from external time cues (exogenous zeitgebers) on our 24 hour cycles, and suggesting that an internal body clock (endogenous pacemaker) creates a free running sleep/wake cycle rhythm of 25 hours. Siffre (1975) * Case study of his own experiences in an underground cave for 2 months. Without any exogenous zeitgebers such as light or cues to guide him, his sleep/wake cycle generally adjusted to a 25 hour cycle, though sometimes changing dramatically up to 48 hours. Aschoff and Weaver (1976) * Designed a temporal isolation study by placing participants in an underground ww2 bunker without an environmental or time cues. * They found that the free running cycle persisted with a sleep wake cycle of 25 hours, sometimes increasing to 29. Weakness into research of circadian rhythms * Lack internal validity. * They removed natural light sources, artificial light from torches and cameras have been shown to reset the endogenous rhythms, thus interfering as an extraneous variable. Exemplified through Czeisler et al (1999) * Altered participants’ circadian rhythms down to 22 hours and up to 28 only using dim lighting to alter his release of melatonin from the pineal gland. * Findings do not reflect true isolation and have lower internal validity, so his rhythm may not have adjusted so well if he had been truly...
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...Class: BBA-8 Circadian Rhythms as a basis of mood disorder, in particular bipolar disorder. Introduction: The complex structure and the functions of the human body has been a subject of study by a lot of individuals since a very long time. The curiosity of the human being supporting it, further aids in discovering the secrets hidden behind the way a human being is. Biological rhythms or circadian rhythms also make up one of the hidden secrets for the functions of the human beings and scheduling of various tasks. The terms Circadian is derived from Latin word Circa, “around” or “about” and diem or dies “day” meaning literally “about a day” or “around a day”. This circadian rhythm is already built in the complex human body but is regulated by external factors known as “zeitgebers”. The primary or the most important zeitgebers is ‘light’ which helps human automatically start a particular process in one’s life and controls various cycles at regular intervals. This may include sleep/wake cycle, eating habits, seasonal affective disorder (SAD) or bipolar disorder. Scientists have long been researching the effects of disturbance of circadian rhythms and its consequences on the life of a human being. This paper also considers the facts that have been established in this area to identify and discuss the process undergoing in a human being and its complexities with a particular reference to circadian rhythms and bipolar disorder, its causes and how...
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...The Consequences of Disrupting Biological Rhythms All living organisms experience rhythmic changes, which tend to coincide with seasonal or daily environmental changes. These rhythms are known as biological rhythms, which include circadian, ultradian and infradian types. All biological rhythms are controlled by two different factors - internally (endogenous) through nature, and externally (exogenous) through nurture. Most organisms have internal biological clocks, called endogenous pacemakers. The main endogenous pacemaker in circadian rhythms is the suprachiasmatic nucleus (SCN), a small bundle of nerves in the hypothalamus, as suggested by Morgan (1995), and Kalat (1998). Kalat suggested that low levels of light lead to an electrical stimulant, which activates the pineal gland in the SCN, located in the centre of the brain, to secrete a hormone called melatonin, which causes sleepiness. Its production of melatonin varies with periods of light and darkness in the environment, and it obtains this information about light in the environment by means of nerve pathways originating in the eyes. Therefore the main exogenous zeitgeber ('time-giver') that controls circadian rhythms is therefore light. Research that suggests the SCN is the main endogenous factor for circadian rhythms comes from Morgan in 1995. His aim was to determine whether the SCN in hamsters is linked to the dissappearance of their circadian rhythms. He removed the SCN from hamsters and transplanted an...
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...Question: Discuss the disruption of biological rhythms (8+ 16 Marks) Biological rhythms are controlled by endogenous pacemakers (Oscillators). endogenous pacemakers can easily be changed by exogenous Zeitgebers such daylight. However if the oscillators are more resistant this can lead to desynchronisation. The most common type of disruption to biological rhythms are shift work and Jet lag. Shift work described a type of job in which individuals have to be alert at night when they work, and they sleep during the day. This results in reduced quality of sleep because it goes against our natural biological rhythms as daytime sleep can be interrupted due to exogenous zeitgebers such as light and outside noise. One of the effects of shift lag has been found to be decreased alertness. Shift workers often experience a circadian trough where there alert levels plummet. This usually occurs between 12.00am and 4.00am and is due to reduced body temperature and a decrease in cortisol levels. This predicted effect of shift work has been supported by research by Moor Ede. It has been found that the decreased alertness as a result of shift lag costs the USA $70 billion per year. More evidence comes from the 3 Mile Island nuclear power station disaster, which occurred at around 4am, and similarly the Exon Val Dez oil tanker accident occurred at 12am and resulted in the spillage of oil in the oceans affecting thousands of wildlife. A second effect of shift work is believed to be the increased risk of...
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...Sleep–waking cycles are fundamental in human circadian rhythms and their disruption can have consequences for behaviour and performance. Such disturbances occur due to domestic or occupational schedules that do not permit normal sleep quotas, rapid travel across multiple meridians and extreme athletic and recreational endeavours where sleep is restricted or totally deprived. There are methodological issues in quantifying the physiological and performance consequences of alterations in the sleep–wake cycle if the effects on circadian rhythms are to be separated from the fatigue process. Individual requirements for sleep show large variations but chronic reduction in sleep can lead to immuno-suppression. There are still unanswered questions about the sleep needs of athletes, the role of ‘power naps’ and the potential for exercise in improving the quality of sleep. © 2006 Elsevier Inc. All rights reserved. Keywords: Circadian rhythm; Exercise; Jet-lag; Shift-work 1. Introduction The sleep–wakefulness cycle is the most discernable of human circadian functions, activity being associated with the hours of daylight and sleep with the hours of darkness. This recurrence on a daily basis is linked with responses of the pineal gland to the environment, its secretion of melatonin being promoted at dusk and inhibited on exposure to morning light. There is a myriad of other biological functions that are knit into a common system of circadian rhythms, cycles in behaviour and in biological functions...
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...being stated, shift work is a requirement in the healthcare field. Sleep deprivation is the lack of sleep due to an external stimulus preventing the opportunity of sleeping and this is a commonly known result of shift work in nurses. Sleep disorders commonly occur with nurses who work rotating shifts. Sleep quality is important, but sleep is not just about how many hours you get. Night shift workers have to sleep during the day which may interfere with their body’s rhythm telling them it is daytime and this jeopardizes their sleeping. This is where sleep deprivation comes into play. Shift work is a major source of disturbances in the healthcare profession. Most healthcare employees have no say over which shift they work. Chan (2008) studied this by using subjective measurements. The Karolinska Sleep Questionnaire was used to address nurses’ sleep patterns. Chan (2008) found that sleep deprivation causes symptoms such as arousals, exacerbations of gastrointestinal problems, and lowers threshold. This is because the stress system is activated by this sleep situation and neuro-hormonal stress act in response and alters the immune system, which then effects the cognitive and limbic systems (Chan, 2008). Strain is put on nurses who are sleep deprived from rotating shifts. Indications of sleep deprivation include headaches, gastric pain, neck and back pain, fatigue, depression, job stress, and sleep disturbances. Compared to nurses who work fixed day shifts to...
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...Shift work sleep disorder. Today's American society functions in the environment of a 24/7 economy. This situation is certainly welcomed by employers and consumers, but what about workers who are required to work outside of the regular 8-5 schedule? What is the impact of shift work on the individual’s health, and especially sleep? Research evidence suggests that shift workers are at a higher risk for developing a wide range of diseases, including cardiovascular disease, obesity, diabetes, gastrointestinal problems, and sleep disturbances. In addition, sleep disorders in shift workers pose a serious risk to public health and safety because they impair an individual’s ability to perform effectively, and may result in occupational and traffic accidents. Employees, who work night shift on a regular or rotating basis, are at risk of developing shift work sleep disorder (SWSD) (Keller, 2009). SWSD belongs to the group of circadian rhythm sleep disorders. Circadian rhythms are the natural internal body mechanisms that regulate body wake/sleep cycle. When circadian rhythms are disturbed the person may experience warning signs of SWSD. The two main symptoms of SWSD are excessive sleepiness at night, during working hours, and insomnia during daytime sleeping hours. SWSD is widely undiagnosed and undertreated in the medical community. The diagnosis usually based on the patient’s history alone, when sleep disturbances cannot be explained by any medical problem, medication, or substance...
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...A system that regulates an internal setting as well as managing a stable, constant condition of properties is homeostasis; essentially its function is maintaining stability and balance in our bodies constantly. External things, such as medications, medical conditions, stress, our diet and what an individual’s sleep environment is like can create a negative impact one’s sleep-wake needs (Brain Basics: Understanding Sleep. (n.d.). Homeostasis fights these negative influences and does its best to keep our bodies in balance, such as our heart rate, breathing, body temperature and even our blood sugar levels. Fundamentally homeostasis keeps track of and triggers the body to sleep and determines the intensity of sleep (Brain Basics: Understanding...
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...In modern day society there is an increasing need to work longer 24hour shifts. using your knowledge of biological rhythms and their impacts disscuss the impact of these demands. Shift work is a work pattern that falls outside of the normal 9-5 working hours. Shift hours came into place firstly in hospitals. This was because the patients needed round the clock care. Another place where shift work came into place was in factories. However even though there are advantages to this type of work there are negatives too, one of these is that there are major disruptions to the employee’s sleep patterns. Most sleep is needed during the times of 2-4 am. This is when most shift workers will struggle to get through their shift. Another reason why it affects them is because it changes the circadian rhythm. The circadian rhythm is a 24hour rhythm which a person recognises and it tells the person to sleep when it is dark and to wake when it is light. This is affected by shift work because they spend most their time under artificial light. Another reason why they struggle is because when the lights go off they need to make sure that they stay awake in case there us an emergency of some kind. Employees can sometimes be offered a night shift where they can have a couple of hours sleep, however they opt out of this type of contact because it pays less than what a night shift without sleeping does. Employers hardly ever give out these types of contract because they feel that they cannot justify...
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...Institute Circadian rhythms are regular changes in mental and physical characteristics that occur in the course of a day (circadian is Latin for "around a day"). Most circadian rhythms are controlled by the body's biological "clock." This clock, called the suprachiasmatic nucleus or SCN, a pair of pinhead-sized brain structures that together contain about 20,000 neurons. The SCN rests in a part of the brain called the hypothalamus, just above the point where the optic nerves cross. Light that reaches photoreceptors in the retina (tissue at the back of the eye) creates signals that travel along the optic nerve to the SCN. Signals from the SCN travel to several brain regions, including the pineal gland, which responds to light-induced signals by switching off production of the hormone melatonin. The body's level of melatonin normally increases after darkness falls, making people feel drowsy. The SCN is synchronized with the sleep/wake cycle, including body temperature, hormone secretion, urine production, and changes in blood pressure. Sunlight or other bright lights can reset the SCN, our biological cycles normally follow the 24-hour cycle of the sun, rather than our innate cycle. Circadian rhythms can be affected to some degree by almost any kind of external time cue, such as the beeping of your alarm clock, the clatter of a garbage truck, or the timing of your meals. Scientists call external time cues zeitgebers (German for "time givers"). Circadian rhythms is the sleep/wake...
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...greater study, where the marine engineers answered a medical questionnaire and filled a diary. Test persons wore also a special watch that recorded their sleep and wake results. This Master Thesis and its results are based on the answers given in the medical questionnaire. Questionnaire was filled in on Swedish vessels operating in different maritime sectors. The results indicated that there were differences between engine personnel’s sleeping habits and especially in how they felt the fatigue. The results received from the medical questionna ire point out that there is a demand at some level for planning, execution and surveillance of marine engineers’ work task. To prevent fatigue in the engine room is current and desirable. The individual circadian rhythm could be taken in consideration when planning work shifts. Work and especially sleeping environment should be suitable. Respecting the...
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...Effects Of Shift Work On The Paramedic Shift work allows for continuous services to be available on a 24-hour basis. This type of “irregular” work schedule is particularly prevalent in the healthcare industry. Among these workers are Paramedics whom form a unique part of the emergency services. As pre-hospital providers they are constantly faced with heavy workloads that are not only physically, but also mentally and emotionally taxing. Fatigue, digestive problems and family conflicts are some factors that may compromise the worker’s aptitude and possibly jeopardize patient safety and the paramedics’ health and overall well-being. The body has its own "biological" clock the helps maintain complex internal functions throughout a 24-hr day. This daily rhythm is known as the circadian rhythm. It is influenced by factors such as light, dark, social contacts, and noise. The human body is meant to be active during daytime hours, and is meant to recover and reenergize during the nighttime hours. Working at night and sleeping during the day is opposite to the body's "biological" clock and what the body naturally wants to do. This may make sleeping difficult, and hamper the body’s ability to recover from the physical and mental demands of a paramedic’s job. Circadian rhythms have been found to be associated with changes in mental and physical performance. Circadian rhythms may partly explain why job performance can vary over a 24-hour period, with a low point occurring very late...
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...Running head: BENEFITS OF SLEEP MEDICINE Benefits of Sleeping Pills May Outweigh the Harm Andrew V. Pham Georgia Perimeter College Abstract The article, “The Case for Sleep Medicine” published by The New York Times, discusses the issue of many Americans' dependence on sleep medicine by thoroughly explaining the effects of sleep deprivation, the risks of relying on these medicine, and the significance of natural sleep to maintain a healthy lifestyle. Gayle Green, the author of this article, states that sleep deprivation has caused many Americans to rely on sleeping pills to obtain enough sleep to function appropriately for work and other activities. This paper examines a study in the BMJ journal that discusses the risks of sleeping pills, and a research administered by researchers from the University of Chicago that depicts the negative effects of sleep deprivation. The article effectively uses these studies and research results to illustrate the many mental and physical complications that result from taking sleep medicine continuously for a period of time, but it seems as though many individuals are willing to accept the increase of risky body malfunctions rather than to lose sleep. Benefits of Sleeping Pills May Outweigh the Harm Sleep is fundamental for survival. It is the body's natural way of restoring itself from daily mental and physical activities. For young adolescents, adequate sleep leads to improved development in the brain and bodily growth....
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...school start times should start later or earlier How many times a day do you feel tired or exhausted, just wanting to go home and sleep and forget all about homework and other commitments that you need to pursue? Do you find it extremely difficult to get out of bed in the morning and get ready for the day? Well, if you answered yes to any of these questions, you’re not alone. It has been excessively studied that adolescents generally have a harder time getting ready for the day in the morning compared to adults; who have lower risk of stress and a higher chance of information retainment. Teenagers go to school from eight in the morning to about three thirty in the afternoon and are expected to do homework from that school day, go to work, practice for sports, and hang out with friends and family and do chores, but yet more times than not, teens are not able to do any extracurricular activities because of how exhausted they are. Studies have shown, teens who begin school at an earlier time have an increased risk of depression, anxiety, obesity, and illness, compared to students who start school at a later time. Starting at puberty, adolescents internal...
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...TABLE OF CONTENTS CHAPTER 1 : INTRODUCTION 1.1 BACKGROUND OF THE STUDY 4 CHAPTER 2 : LITERATURE REVIEW 2.1 Introduction 5 2.2 Interfacing between Human and Other Elements. 6 2.3 Factors Affecting Performances 6 2.3.1 Fitness and Health 5 2.3.2 Stress 7 2.3.3 Workload 10 2.3.4 Sleep 13 2.3.5 Circadian Rhythms 15 2.3.6 Fatigue & Shift Work 17 2.3.7 Alcohol, Medication and Drug Abuse 23 2.3 FACTOR AFFECTING PERFORMANCE 32 2.4 TYPES OF ERROR IN AVIATION 36 2.5 MANAGING ERROR IN AVIATION 36 CHAPTER 3 : CONTENTS 38 CHAPTER 4 : RECOMMENDATION AND CONCLUSION 42 REFRENCES 43 CHAPTER 1 : INTRODUCTION Errors are the result of actions that fail to generate the intended outcomes. In common with most other complex technical activities, human error is implicated in the majority of aviation-maintenance-related quality lapses, incidents, and accidents. General estimates of this human error contribution have increased over the years, from a low of around 20% in the 1960s to values in excess of 80% in the 1990s. Human error in aviation is somewhat of a sensitive topic due to the recent tragic events of September 11, 2001. The goal of this research is to understand human error in aviation, in order to understand how designing better computer systems can assist in making the aviation industry safer for pilots and passengers, by reducing...
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