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Medications
Published in Henry J. Woodford, Essential Geriatrics, 2022
Melatonin is an endogenous hormone produced at night by the pineal gland and plays a role in maintaining normal circadian rhythm. Its production may be reduced in older people. There has been hope that this could be a safer, yet effective, alternative. Unfortunately, some data suggest that the risk of falls and fractures may be as high with melatonin as that seen with benzodiazepines or Z-drugs.41 In addition, melatonin only has a small effect on sleep. A meta-analysis found that, on average, users fell asleep just seven minutes quicker and slept for just eight minutes longer than people given a placebo.42
Sleep–Wake Disorders
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Margaret Kay-Stacey, Eunice Torres-Rivera, Phyllis C. Zee
Sleep and circadian rhythm disorders are common, and can increase the risk, as well as contribute to the expression and severity of common medical, neurologic, and psychiatric disorders. Given the frequent overlap of sleep disturbance with many neurologic conditions, neurologists are well positioned to identify and provide treatment of sleep–wake disorders. A basic sleep history, including questions about snoring, sleep habits, sleep initiation and continuity, daytime fatigue or sleepiness, leg symptoms, and bed partner complaints, should become a part of every neurologic evaluation. Addressing sleep disorders will not only help improve sleep quality, but also optimize treatment of comorbid disorders.
Fibromyalgia
Published in Sahar Swidan, Matthew Bennett, Advanced Therapeutics in Pain Medicine, 2020
Melatonin is an indole neurohormone compound that is produced in the brain by the pineal gland.170 The synthesis and release of melatonin in the body are stimulated by darkness and suppressed by light, suggesting that melatonin is involved in circadian rhythm. Melatonin is thought to decrease the severity of pain, as well as the number of painful joints in people with fibromyalgia.171 Fibromyalgia patients have been shown to have altered levels of melatonin and its precursors, serotonin and tryptophan. Additionally, lower nighttime and higher daytime melatonin levels have been measured in this population. These factors may play a role in the sleep disturbances at night and pain and fatigue during the day that are commonly seen in this population, making melatonin an interesting compound to study for fibromyalgia.172 The suggested dose of melatonin is 3 mg to 5 mg daily for up to 60 days.171 Studies exploring the use of melatonin for fibromyalgia have used doses from 3 mg to 15 mg daily for a period of 10 days to 60 weeks.172
Temperature compensation and entrainment in cyanobacteria circadian rhythm
Published in Chronobiology International, 2023
Circadian rhythms can also be reset by external environmental signals, such as periodic temperature or light, which is known as entrainment. Temperature entrainment is adaptation of circadian rhythms to external periodic temperature (Johnson and Egli 2014). Temperature entrainment and temperature compensation are two characteristics of circadian rhythm coexisting with each other. When the influence of external environment on circadian period is small, it is easier to produce temperature compensation, but entrainment is difficult to realize. On the contrary, when the external environment has a great impact on circadian period, entrainment is easy to appear, but the characteristics of temperature compensation will be weakened accordingly. We want to explore how these two seemingly contradictory characteristics are realized in cyanobacteria circadian rhythm.
Impaired biological rhythm in men with methamphetamine use disorder: the relationship with sleep quality and depression
Published in Journal of Substance Use, 2023
Chronobiology is concerned with the timing of biological events, particularly repetitive or cyclical events, in organisms. Circadian rhythm refers to biological variations or rhythms with a cycle of approximately 24 hours (Vitaterna et al., 2001). The most widely used biological rhythm is the circadian rhythm. Although the circadian system in humans consists of the suprachiasmatic nucleus (SCN), retina, pineal gland and retinohypothalamic tract, the center responsible for the circadian rhythm is the SCN located in the anterior hypothalamus, also known as the biological clock. The circadian rhythm is primarily synchronized by light. Apart from light, it is also regulated by social rhythm givers (Social Zeitgeber). These are social factors, such as the hours when social interactions, work, exercise, bedtime and wake-up times, and meals occur (Selvi et al., 2011a).
Network structure of insomnia symptoms in shift workers compared to non-shift workers
Published in Chronobiology International, 2023
Eun Jung Cha, Young Rong Bang, Hong Jun Jeon, In-Young Yoon
One factor that is often discussed to be strongly associated with insomnia is shift work (Vallieres et al. 2014). Shift work is defined as any type of work with work hours outside the traditional 9 a.m. to 5 p.m. (McMenamin 2007). Shift work is essential in jobs that require a 24-hour service, such as healthcare. However, shift work disrupts circadian rhythm, which poses many risks and vulnerabilities to various health problems, including insomnia (Drake et al. 2004; Vallieres et al. 2014). One study reported prevalence of insomnia symptoms in nurses working shift rotations to be around 28.9% to 40.7% (Flo et al. 2012). Commonly associated insomnia symptoms of shift workers include difficulty in initiating sleep, nocturnal awakening, daytime sleepiness, and poor overall sleep quality (Cheng and Cheng 2017; Ohayon et al. 2002; Yong et al. 2017). In addition, insomnia in shift workers is attributed to be a major cause of work-related accidents (Ohayon and Hong 2002), which can be critical in healthcare settings. Factors that affect insomnia symptoms in shift workers were reported to be off-hours between work shifts (Eldevik et al. 2013), anxiety levels (Leyva-Vela et al. 2018), gender, and circadian type (Flo et al. 2012; Jeon et al. 2017). Other factors that were more prevalent in shift workers include stress and anxiety (Kim et al. 2019). Insomnia symptoms in shift workers also exacerbate existing physical and mental problems, such as chronic pain, anxiety, and depression (Vallieres et al. 2014).