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Altitude, temperature, circadian rhythms and exercise
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Henning Wackerhage, Kenneth A. Dyar, Martin Schönfelder
Interindividual differences in athletic performance are based on relationships between genes and the environment. These interactions may also determine relative time-of-day differences in athletic performance. For example, a person’s preferred time of sleep and activity, termed chronotype, is a behavioural manifestation of complex interactions between environmental time and their personal biological time, which is determined by their genetically coded circadian clock (65). Human chronotypes show large variation, with phase differences between extreme early and extreme late chronotypes spanning across 12 h. Earlier chronotypes perform better in the morning, whereas later chronotypes perform better in the evening (62). While each age group shows normal distribution among early and late chronotypes, average chronotype changes according to sex, and throughout one’s lifetime according to age (66). Finally, athletes travelling across time zones for competitions may experience jet lag, which is an abrupt mismatch between their internal biological time and their external environmental time. This can result in sleep disturbances, increased lethargy, digestive problems, and impaired cognitive and physical performance (67). These issues tend to be worse than the more time zones that are crossed, and particularly when travelling East rather than West.
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
Diagnosis is established by a detailed history and a sleep diary and/or actigraphy and questionnaires to assess for morning or early chronotype. The patient should exhibit an advance in sleep–wake timing (Figure 28.32) associated with daytime impairments or distress. When allowed to sleep during their preferred time, sleep quality and duration are normal. The differential diagnosis includes early morning awakening associated with depression or sleep maintenance insomnia.
Air Pollution
Published in William J. Rea, Kalpana D. Patel, Air Pollution and the Electromagnetic Phenomena as Incitants, 2018
William J. Rea, Kalpana D. Patel
The human endogenous master clock has evolved to recognize a regularly occurring, 24-hour pattern of light and dark. There are, of course, genetic differences among individuals, so the coupling between the highly predictable 24-hour solar day and one's own internal clock will differ to some degree. For example, individuals can be characterized by what is termed their chronotype;44 some people are larks, rising early in the day and going to bed early at night, while others are owls, going to bed late and, if they can, rising late in the morning. Interestingly, as individuals reach puberty, the propensity to become more owl-like increases until, when one reaches young adulthood, he or she returns to a more “normal” pattern of sleep-wake.45 Toward the end of an individual's life, apoptosis begins to become problematic for many physiological systems, including circadian regulation. One begins to lose retinal neurons, compromising not only the ability to see, but also the ability to register the robust daily pattern of light-dark that is needed to maintain entrainment. Individuals also lose neurons in the master clock itself, particularly in persons with Alzheimer's disease (AD),46,47 further compromising our ability to synchronize both physiology and behavior to the 24-hour day.
Changes in menstrual cycle length and in sleep-wake behaviors during COVID-19 related lockdown in Israel
Published in Health Care for Women International, 2023
Anat Lan, Tal Ron, Yelena Stukalin, Noga Kronfeld-Schor, Haim Einat
An additional important factor that may moderate the effects of lockdown is the individual differences in sleep-wake cycles. Human sleep-wake behavior is timed by the interaction between an intrinsic biological clock synchronized to the light/dark cycle, a homeostatic sleep drive, and social schedules (Roenneberg et al., 2007; Skeldon et al., 2017). The innate timing of sleep can be described by an individual’s morningness/eveningness preference and can be classified as ‘early’, intermediate or ‘late’ chronotype relative to people measured under similar conditions (Roenneberg & Merrow, 2016). Early chronotypes spontaneously wake up early in the morning and go to sleep early at night, while late chronotypes wake up late in the morning (or noon) and go to sleep late at night or early morning. Chronotypes have a normal distribution in the general population (Roenneberg, 2015). Because most people live according to the same social time, late chronotypes often experience a greater misalignment between their internal biological time and external work/social time. Such misalignment is termed ‘social jetlag’ (SJL) (Wittmann et al., 2006). During lockdown, compared to a pre-lockdown condition, it was found that in young participants, late chronotypes sleep duration was increased more than the sleep duration of early chronotypes (Oved et al., 2021). Under regular conditions, late chorotypes suffer a substantial sleep loss (Wittmann et al., 2006) while during lockdown the mismatch between social and intrinsic clock is reduced, allowing late chronotypes to increase their sleep duration.
Validation of the Munich Chronotype Questionnaire (MCTQ) in Chinese college freshmen based on questionnaires and actigraphy
Published in Chronobiology International, 2023
Shuo Wang, Haien Wang, Xinyi Deng, Xu Lei
An individual’s unique biological clock influences their preferred and actual daily sleep and activity patterns (Roenneberg et al. 2019). A chronotype is defined as an individual’s circadian preference (e.g., an evening chronotype) or their phase of entrainment (e.g., the mid-sleep point on free days) (Taylor and Hasler 2018). A chronotype comprises three circadian types: morning (larks), intermediate, and evening (owls). Morning chronotypes prefer to go to bed early and wake up early. Evening chronotypes tend to sleep later and get up later. Most individuals fall along the “intermediate” or “neither” chronotype (Adan et al. 2012). As a measure of individual differences in resting and activity time preference, the chronotype is becoming an increasingly important correlate of mental health (Levandovski et al. 2013). For example, having an evening chronotype increases the risk of sleep problems (Alvaro et al. 2014), mood disorders (Abreu and Braganca 2015; Adan et al. 2012; Au and Reece 2017), and metabolic disorders (Yu et al. 2015). Furthermore, people with evening chronotypes are more likely to engage in creative thinking (Giampietro and Cavallera 2007), and musicians have a tendency towards eveningness (Gjermunds et al. 2019).
Investigation of the relationship between chronotype, learning style and academic achievement of university students during distance education in the pandemic period
Published in Chronobiology International, 2022
Özgül Balcı, Muhittin Çalışkan
Regarding age, although it is known that chronotype stays stable in short time spans, it does change significantly throughout the life span (Randler and Engelke 2019; Randler et al. 2017). Studies show that although children are more morning-oriented, they show a strong tendency towards eveningness in puberty, at about the age of 13 (Kim et al. 2002), and slowly shift to morningness again from the age of 17–20 years (Randler and Engelke 2019; Randler et al. 2017, 2016). In particular, adolescence is a significant period when the sleep and wake schedules tend to become delayed (Carskadon et al. 1993; Montaruli et al. 2017), influencing physical health, cognitive and affective functions (Montaruli et al. 2017) as well as physical performance (Roveda et al. 2020). Nonetheless, sociocultural factors were reported as a factor that might influence chronotype preferences in different age groups in significantly different ways for certain cultures (Randler et al. 2014). As for the university students, who are at the end of adolescence and closer to reaching their maximum eveningness (Roenneberg et al. 2004) and are the focus of this current study, studies show that majority of the population was found to be N types, some were E types, while only few students were found to be M types (Adan and Natale 2002; Chelminski et al. 1997; Enright and Refinetti 2017; Jovanovski and Bassili 2007). However, Beşoluk et al. (2011) reported that although majority of the students were N types, unlike other studies, the number of the M types was higher than the E types in their study.