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group_3_presentation_2_-_how_sleep_influences_the_body [2020/02/27 19:38] mehmoodm |
group_3_presentation_2_-_how_sleep_influences_the_body [2020/02/27 22:35] (current) gorganir |
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| ===============How Sleep Influences The Body=============== | ===============How Sleep Influences The Body=============== | ||
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| + | =====Presentation Slides===== | ||
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| =====Introduction===== | =====Introduction===== | ||
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| Sleep is characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity, as well as the inhibition of nearly all voluntary muscles during deep sleep (John Hopkins Medicine, n.d.). There is a decreased overall reactivity to stimuli, but those who are asleep still show unique and active brain signals. During sleep, most of the body’s systems are in an anabolic state which helps to restore the immune, nervous, muscular, and skeletal systems; these are extremely vital processes that help to maintain a healthy mood, memory, and cognitive functions, and also plays are large role in ensuring proper functions of the endocrine and immune systems (John Hopkins Medicine, n.d.). | Sleep is characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity, as well as the inhibition of nearly all voluntary muscles during deep sleep (John Hopkins Medicine, n.d.). There is a decreased overall reactivity to stimuli, but those who are asleep still show unique and active brain signals. During sleep, most of the body’s systems are in an anabolic state which helps to restore the immune, nervous, muscular, and skeletal systems; these are extremely vital processes that help to maintain a healthy mood, memory, and cognitive functions, and also plays are large role in ensuring proper functions of the endocrine and immune systems (John Hopkins Medicine, n.d.). | ||
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| + | <box 30% round center|> {{ :group3img6.png?300 |}} </box| Figure 1. The circadian rhythm (APR, 2019)> | ||
| The internal circadian rhythm promotes daily sleep at night. This is our “internal clock” that recognizes the difference between day and night and ensures that our bodies are well rested at night in order to function properly throughout the day. The internal circadian rhythm is what causes individuals to become “jet-lagged” when they travel to different time-zones. Humans’ need for sleep varies depending on the individual; sleep is considered to be adequate when there is no daytime sleepiness or dysfunction (John Hopkins Medicine, n.d.). This would indicate that the body has fully replenished overnight and is able to function properly throughout the day. Age also plays a role in how much sleep individuals need on a given night. Younger children require more sleep in order to develop and function properly: up to 18 hours for newborns, with the rate decreasing as the child ages. The recommended amount of sleep for adults is between 7 to 9 hours per night (John Hopkins Medicine, n.d.). | The internal circadian rhythm promotes daily sleep at night. This is our “internal clock” that recognizes the difference between day and night and ensures that our bodies are well rested at night in order to function properly throughout the day. The internal circadian rhythm is what causes individuals to become “jet-lagged” when they travel to different time-zones. Humans’ need for sleep varies depending on the individual; sleep is considered to be adequate when there is no daytime sleepiness or dysfunction (John Hopkins Medicine, n.d.). This would indicate that the body has fully replenished overnight and is able to function properly throughout the day. Age also plays a role in how much sleep individuals need on a given night. Younger children require more sleep in order to develop and function properly: up to 18 hours for newborns, with the rate decreasing as the child ages. The recommended amount of sleep for adults is between 7 to 9 hours per night (John Hopkins Medicine, n.d.). | ||
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| + | <box 30% round center|> {{ :group3img7.png?300 |}} </box| Figure 2. Hours of sleep required per night (Hirshkowitz et al., 2015)> | ||
| =====Factors That Disturb Sleep===== | =====Factors That Disturb Sleep===== | ||
| There are several factors that can disturb the balance of our circadian rhythm. One common factor is blue light exposure. Sources of blue light include the sun, digital screens, and LED light. Blue light suppresses the secretion of melatonin, a hormone that promotes sleepiness and shifts circadian rhythms (Harvard News Letter, 2018). | There are several factors that can disturb the balance of our circadian rhythm. One common factor is blue light exposure. Sources of blue light include the sun, digital screens, and LED light. Blue light suppresses the secretion of melatonin, a hormone that promotes sleepiness and shifts circadian rhythms (Harvard News Letter, 2018). | ||
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| Inconsistent sleep schedules are another factor that disrupts sleep. The body is unable to establish a circadian clock, which leads to difficulty in falling asleep (Kang & Chen, 2009). Stress is also a factor that alters the sleep-wake cycle. Stress triggers the autonomic nervous system to release hormones, such as adrenaline and cortisol. These hormones are responsible for a reaction known as the flight-or-fight response, which raises one’s alertness and promotes arousal. Frequently being in a heightened state of alertness can delay the onset of sleep and adversely affect one’s sleep quality (Johnson, 2018). | Inconsistent sleep schedules are another factor that disrupts sleep. The body is unable to establish a circadian clock, which leads to difficulty in falling asleep (Kang & Chen, 2009). Stress is also a factor that alters the sleep-wake cycle. Stress triggers the autonomic nervous system to release hormones, such as adrenaline and cortisol. These hormones are responsible for a reaction known as the flight-or-fight response, which raises one’s alertness and promotes arousal. Frequently being in a heightened state of alertness can delay the onset of sleep and adversely affect one’s sleep quality (Johnson, 2018). | ||
| Many would assume exercising before bed will also negatively impact sleep quality as it is another activity that stimulates cortisol release. However, scientists found that vigorous late-night exercise has no association with sleep and does not affect sleep quality (Myllymäki, et al., 2011). The effect of caffeine on sleep is another controversial discussion. Over the years, researches showed contradicting findings. One study suggested that consumption of caffeine 6 hours before bedtime has a significant disruptive effect on sleep. On the other hand, another study examined the relationship between caffeine, alcohol, nicotine, and sleep. Nicotine and alcohol use within 4 hours of bedtime was associated with increased sleep fragmentation, but caffeine was not associated with any of the sleep parameters (Spadola, et al., 2019). The effect of caffeine appears to vary among individuals. | Many would assume exercising before bed will also negatively impact sleep quality as it is another activity that stimulates cortisol release. However, scientists found that vigorous late-night exercise has no association with sleep and does not affect sleep quality (Myllymäki, et al., 2011). The effect of caffeine on sleep is another controversial discussion. Over the years, researches showed contradicting findings. One study suggested that consumption of caffeine 6 hours before bedtime has a significant disruptive effect on sleep. On the other hand, another study examined the relationship between caffeine, alcohol, nicotine, and sleep. Nicotine and alcohol use within 4 hours of bedtime was associated with increased sleep fragmentation, but caffeine was not associated with any of the sleep parameters (Spadola, et al., 2019). The effect of caffeine appears to vary among individuals. | ||
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| Last but not least, eating near bedtime may also undermine sleep. While some food, such as warm milk and chicken breast, may help us relax and contain chemicals that promote sleep, spicy and acidic food like citrus and tomatoes can induce heartburn, which can lead to insomnia (Peters, 2019). | Last but not least, eating near bedtime may also undermine sleep. While some food, such as warm milk and chicken breast, may help us relax and contain chemicals that promote sleep, spicy and acidic food like citrus and tomatoes can induce heartburn, which can lead to insomnia (Peters, 2019). | ||
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| =====Consequences of Sleep Deprivation===== | =====Consequences of Sleep Deprivation===== | ||
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| Getting a good quality of sleep is critical for the endocrine system to operate effectively. Significant hormonal changes affecting the hypothalamic-pituitary-adrenal (HPA) axis activity take place in the setting of sleep deprivation (Sleep and the Endocrine Brain, 2020). The HPA axis plays a critical role in the stress response, a neuroendocrine adaptation component that has been evolutionarily developed. The stress response initiates with the stimulatory release of corticotropin-releasing hormone (CRH) in the hypothalamus. The CRH binds to CRH receptors on the anterior pituitary gland, which stimulates the release of its hormone, or adrenocorticotropic hormone (ACTH). ACTH then binds to receptors on the adrenal cortex and stimulates the release of cortisol. In response to the stressors, cortisol will be released for several hours after encountering the stressor (Medscape, 2020). | Getting a good quality of sleep is critical for the endocrine system to operate effectively. Significant hormonal changes affecting the hypothalamic-pituitary-adrenal (HPA) axis activity take place in the setting of sleep deprivation (Sleep and the Endocrine Brain, 2020). The HPA axis plays a critical role in the stress response, a neuroendocrine adaptation component that has been evolutionarily developed. The stress response initiates with the stimulatory release of corticotropin-releasing hormone (CRH) in the hypothalamus. The CRH binds to CRH receptors on the anterior pituitary gland, which stimulates the release of its hormone, or adrenocorticotropic hormone (ACTH). ACTH then binds to receptors on the adrenal cortex and stimulates the release of cortisol. In response to the stressors, cortisol will be released for several hours after encountering the stressor (Medscape, 2020). | ||
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| + | <box 40% round center|> {{ :group3img18.png?400 |}} </box| Figure 3. Mechanism of the HPA Axis (Mong et al., 2010)> | ||
| Good quality of sleep maintains and regulates the HPA activity to a body’s optimum level, establishing homeostasis. However, activation of the HPA axis by a stressor is known to disrupt normal sleep patterns (Trayhurn, 2005). Hence, lack of sleep can heighten an individual’s sensitivity to stress. | Good quality of sleep maintains and regulates the HPA activity to a body’s optimum level, establishing homeostasis. However, activation of the HPA axis by a stressor is known to disrupt normal sleep patterns (Trayhurn, 2005). Hence, lack of sleep can heighten an individual’s sensitivity to stress. | ||
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| Sleep consists of two main phases, non‐rapid‐eye‐movement sleep (NREM) and rapid‐eye‐movement (REM) sleep. A measure of vigilance can be obtained by measuring brain electrical activity with electroencephalography (EEG). In EEG, waking is characterized by low‐amplitude, high‐frequency waves. During NREM sleep, the amplitude of EEG waves increases and the frequency decreases, while in REM sleep, EEG is indistinguishable from waking state. These states can be separated based on muscle activity (measured using electromyography, EMG) and saccadic eye movements (measured using electro‐oculography, EOG). During waking, muscle activity is high; in NREM sleep, it decreases; and in REM sleep, it practically disappears. | Sleep consists of two main phases, non‐rapid‐eye‐movement sleep (NREM) and rapid‐eye‐movement (REM) sleep. A measure of vigilance can be obtained by measuring brain electrical activity with electroencephalography (EEG). In EEG, waking is characterized by low‐amplitude, high‐frequency waves. During NREM sleep, the amplitude of EEG waves increases and the frequency decreases, while in REM sleep, EEG is indistinguishable from waking state. These states can be separated based on muscle activity (measured using electromyography, EMG) and saccadic eye movements (measured using electro‐oculography, EOG). During waking, muscle activity is high; in NREM sleep, it decreases; and in REM sleep, it practically disappears. | ||
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| + | <box 40% round center|> {{ :group3img13.png?400 |}} </box| Figure 4. EEG of different stages of sleep (Porkka‐Heiskanen et al., 2013)> | ||
| During REM sleep, eyes undergo characteristic rapid movements, of which the state has got its name. A finer division of NREM sleep is based on the proportion of the low‐frequency, high‐amplitude waves (called slow‐wave activity, SWA). NREM sleep is divided into three stages (S1, S2 and S3) in increasing order of SWA. Sleep stages alternate in the course of the night in a regular manner: sleep starts by S1 and deepens via S2 to S3 and then proceeds to REM sleep. After the REM sleep period, the cycle starts from the beginning. The duration of one sleep cycle is about 90 min. The sleep stages calculated across the night are often presented as a hypnogram, which describes the order and duration of each sleep stage. During SWA sleep, virtually all cortical neurons are engaged in a slow (<1 Hz) oscillation consisting of alternating ON and OFF periods. During ON periods, cortical cells are depolarized and fire action potentials at a high rate, while during OFF periods, cells are hyperpolarized and silent. (Porkka-Heiskanen et al., 2013) | During REM sleep, eyes undergo characteristic rapid movements, of which the state has got its name. A finer division of NREM sleep is based on the proportion of the low‐frequency, high‐amplitude waves (called slow‐wave activity, SWA). NREM sleep is divided into three stages (S1, S2 and S3) in increasing order of SWA. Sleep stages alternate in the course of the night in a regular manner: sleep starts by S1 and deepens via S2 to S3 and then proceeds to REM sleep. After the REM sleep period, the cycle starts from the beginning. The duration of one sleep cycle is about 90 min. The sleep stages calculated across the night are often presented as a hypnogram, which describes the order and duration of each sleep stage. During SWA sleep, virtually all cortical neurons are engaged in a slow (<1 Hz) oscillation consisting of alternating ON and OFF periods. During ON periods, cortical cells are depolarized and fire action potentials at a high rate, while during OFF periods, cells are hyperpolarized and silent. (Porkka-Heiskanen et al., 2013) | ||
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| The two‐process model says that a homeostatic process (Process S) interacts with a process controlled by the circadian pacemaker (Process C), with time‐courses derived from physiological and behavioural variables. The model simulates successfully the timing and intensity of sleep in diverse experimental protocols. Electrophysiological recordings from the suprachiasmatic nuclei (SCN) suggest that Processes S and C interact continuously. A deficiency of Process S was proposed to account for both depressive sleep disturbances and the antidepressant effect of sleep deprivation (Borbely et al., 2016). The homeostatic process represents the need for sleep. It increases while awake and decreases while sleeping. The circadian rhythm depends on the suprachiasmatic nucleus. It is entrained in the external light-dark cycle, firing most rapidly during the light period, under the regulation of a special class of light‐sensitive retinal ganglion cells that contain the photopigment melanopsin. The C process would increase during the sleep state, thus ensuring continued sleep despite the diminishing homeostatic need for it toward the end of the sleep cycle (Saper et al., 2005). | The two‐process model says that a homeostatic process (Process S) interacts with a process controlled by the circadian pacemaker (Process C), with time‐courses derived from physiological and behavioural variables. The model simulates successfully the timing and intensity of sleep in diverse experimental protocols. Electrophysiological recordings from the suprachiasmatic nuclei (SCN) suggest that Processes S and C interact continuously. A deficiency of Process S was proposed to account for both depressive sleep disturbances and the antidepressant effect of sleep deprivation (Borbely et al., 2016). The homeostatic process represents the need for sleep. It increases while awake and decreases while sleeping. The circadian rhythm depends on the suprachiasmatic nucleus. It is entrained in the external light-dark cycle, firing most rapidly during the light period, under the regulation of a special class of light‐sensitive retinal ganglion cells that contain the photopigment melanopsin. The C process would increase during the sleep state, thus ensuring continued sleep despite the diminishing homeostatic need for it toward the end of the sleep cycle (Saper et al., 2005). | ||
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| + | <box 40% round center|> {{ :group3img15.png?400 |}} </box| Figure 5. Two process model of sleep regulation (Patanaik, 2015)> | ||
| Sleep is regulated by the interaction of a variety of neurotransmitter systems in the brainstem, forebrain, and hypothalamus. A core region that is active during REM sleep is the subcoeruleus nucleus (SubC). It is hypothesized that glutamatergic SubC neurons regulate REM sleep and its defining features such as muscle paralysis and cortical activation. REM sleep paralysis is initiated when glutamatergic SubC cells activate neurons in the ventromedial medulla (VMM), which causes the release of GABA and glycine onto skeletal motoneurons. REM sleep timing is controlled by the activity of GABAergic neurons in the ventrolateral periaqueductal gray and dorsal paragigantocellular reticular nucleus as well as melanin-concentrating hormone neurons in the hypothalamus and cholinergic cells in the laterodorsal and pedunculo-pontine tegmentum in the brainstem (Fraigne et al., 2015). | Sleep is regulated by the interaction of a variety of neurotransmitter systems in the brainstem, forebrain, and hypothalamus. A core region that is active during REM sleep is the subcoeruleus nucleus (SubC). It is hypothesized that glutamatergic SubC neurons regulate REM sleep and its defining features such as muscle paralysis and cortical activation. REM sleep paralysis is initiated when glutamatergic SubC cells activate neurons in the ventromedial medulla (VMM), which causes the release of GABA and glycine onto skeletal motoneurons. REM sleep timing is controlled by the activity of GABAergic neurons in the ventrolateral periaqueductal gray and dorsal paragigantocellular reticular nucleus as well as melanin-concentrating hormone neurons in the hypothalamus and cholinergic cells in the laterodorsal and pedunculo-pontine tegmentum in the brainstem (Fraigne et al., 2015). | ||
| - | =====How To Improve Sleep Quality===== | + | <box 40% round center|> {{ :group3img16.png?400 |}} </box| Figure 6. How the brain is involved in sleep regulation (Porkka‐Heiskanen et al., 2013)> |
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| + | =====Conclusion - How To Improve Sleep Quality===== | ||
| Maintaining good sleep hygiene is the key success in promoting a restful night’s sleep. Sleep hygiene refers to healthy sleep habits that can improve one’s sleep quality. There are four main sets of recommendations. First is to have a consistent sleep schedule. This helps the body to maintain a natural circadian rhythm and optimize the quality of sleep. Naps should be taken with caution. While some studies suggest that daytime naps benefit long term memory, other researches demonstrated that improper napping can disturb our circadian rhythm (Cousins, et al., 2019; Mayo Clinic. 2018). | Maintaining good sleep hygiene is the key success in promoting a restful night’s sleep. Sleep hygiene refers to healthy sleep habits that can improve one’s sleep quality. There are four main sets of recommendations. First is to have a consistent sleep schedule. This helps the body to maintain a natural circadian rhythm and optimize the quality of sleep. Naps should be taken with caution. While some studies suggest that daytime naps benefit long term memory, other researches demonstrated that improper napping can disturb our circadian rhythm (Cousins, et al., 2019; Mayo Clinic. 2018). | ||
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| Harvard Health Publishing. (n.d.). Blue light has a dark side. Retrieved from | Harvard Health Publishing. (n.d.). Blue light has a dark side. Retrieved from | ||
| https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side | https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side | ||
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| + | How Does Circadian Rhythm Impact Pilots? | Travel Blog. (2019, April 27). APR Travel Blog. https://www.airportparkingreservations.com/blog/circadian-rhythm-aviation/ | ||
| How to get a great nap. (2018, November 20). Retrieved from | How to get a great nap. (2018, November 20). Retrieved from | ||
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| Spadola, C. E., Guo, N., Johnson, D. A., Sofer, T., Bertisch, S. M., Jackson, C. L., … Redline, S. | Spadola, C. E., Guo, N., Johnson, D. A., Sofer, T., Bertisch, S. M., Jackson, C. L., … Redline, S. | ||
| - | (2019). Evening intake of alcohol, caffeine, and nicotine: night-to-night associations with | + | (2019). Evening intake of alcohol, caffeine, and nicotine: night-to-night associations with sleep duration and continuity among African Americans in the Jackson Heart Sleep Study. Sleep, 42(11). doi: 10.1093/sleep/zsz136 |
| - | sleep duration and continuity among African Americans in the Jackson Heart Sleep | + | |
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| - | Study. Sleep, 42(11). doi: 10.1093/sleep/zsz136 | + | |
| Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272–1278. | Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272–1278. | ||
