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Circadian misalignment increases cardiovascular disease risk factors in humans
Shift work is a risk factor for hypertension, inflammation, and cardiovascular disease. This increased risk cannot be fully explained by classic risk factors. One of the key features of shift workers is that their behavioral and environmental cycles are typically misaligned relative to their endogenous circadian system. However, there is little information on the impact of acute circadian misalignment on cardiovascular disease risk in humans. Here we show—by using two 8-d laboratory protocols—that short-term circadian misalignment (12-h inverted behavioral and environmental cycles for three days) adversely affects cardiovascular risk factors in healthy adults. Circadian misalignment increased 24-h systolic blood pressure (SBP) and diastolic blood pressure (DBP) by 3.0 mmHg and 1.5 mmHg, respectively. These results were primarily explained by an increase in blood pressure during sleep opportunities (SBP, +5.6 mmHg; DBP, +1.9 mmHg) and, to a lesser extent, by raised blood pressure during wake periods (SBP, +1.6 mmHg; DBP, +1.4 mmHg). Circadian misalignment decreased wake cardiac vagal modulation by 8–15%, as determined by heart rate variability analysis, and decreased 24-h urinary epinephrine excretion rate by 7%, without a significant effect on 24-h urinary norepinephrine excretion rate. Circadian misalignment increased 24-h serum interleukin-6, C-reactive protein, resistin, and tumor necrosis factor-α levels by 3–29%. We demonstrate that circadian misalignment per se increases blood pressure and inflammatory markers. Our findings may help explain why shift work increases hypertension, inflammation, and cardiovascular disease risk.
Journal Article
Circadian rhythms : a very short introduction
This volume explains how organisms can 'know' the time and reveals what we now understand of the nature and operation of chronobiological processes. Covering variables such as light, the metabolism, human health, and the seasons, Foster and Kreitzman illustrate how jet lag and shift work can impact on human well-being.-- Source other than Library of Congress.
Book
Circadian rhythms, sleep, and metabolism
The discovery of the genetic basis for circadian rhythms has expanded our knowledge of the temporal organization of behavior and physiology. The observations that the circadian gene network is present in most living organisms from eubacteria to humans, that most cells and tissues express autonomous clocks, and that disruption of clock genes results in metabolic dysregulation have revealed interactions between metabolism and circadian rhythms at neural, molecular, and cellular levels. A major challenge remains in understanding the interplay between brain and peripheral clocks and in determining how these interactions promote energy homeostasis across the sleep-wake cycle. In this Review, we evaluate how investigation of molecular timing may create new opportunities to understand and develop therapies for obesity and diabetes.
Journal Article
Perceptual Image of Sound: A Gestalt Approach
In primitive and early superior cultures, different elements (such as human beings, events, natural phenomena, and objects) were grouped into the same rhythmic category only because they had similar forms. This rhythm—which can be reproduced in a song or on a drum—also characterizes the individual animal, human being, or object because of their unique shape, form, or movement. According to Benveniste’s proposal, the original meaning of “rhythm” (ῥυθμός) was the perception of a “peculiar way of flowing,” or a “spatial configuration defined by the distinctive arrangement and proportion of elements” (my translation). This definition is very similar to that of form/Gestalt/structure/system, that is, a whole that is not the mere sum of its parts but is something more and something new, determined by the relationships among the components. Gestalt psychology originated from the perception of sound and was then applied to the perception of speech, audio-vision, and music. Audio-vision is an illusion, created by the fusion of two signals that come together in a new configuration, a new rhythm, a new form in the subject’s perception. In music, the perception of Gestalt/rhythmic structures is shaped by the changing characteristics of the sound field, which are influenced by the physical data, the musical structure, and the listener’s experiences and expectations. Consequently, music and perception are engaged in a cyclical process of repetition/redundancy/assimilation and change/variation/accommodation that continually reshapes our sound field perceptual organization.
Journal Article
Human circadian variations
Circadian rhythms, present in most phyla across life, are biological oscillations occurring on a daily cycle. Since the discovery of their molecular foundations in model organisms, many inputs that modify this tightly controlled system in humans have been identified. Polygenic variations and environmental factors influence each person's circadian rhythm, contributing to the trait known as chronotype, which manifests as the degree of morning or evening preference in an individual. Despite normal variation in chronotype, much of society operates on a \"one size fits all\" schedule that can be difficult to adjust to, especially for certain individuals whose endogenous circadian phase is extremely advanced or delayed. This is a public health concern, as phase misalignment in humans is associated with a number of adverse health outcomes. Additionally, modern technology (such as electric lights and computer, tablet, and phone screens that emit blue light) and lifestyles (such as shift or irregular work schedules) are disrupting circadian consistency in an increasing number of people. Though medical and lifestyle interventions can alleviate some of these issues, growing research on endogenous circadian variability and sensitivity suggests that broader social changes may be necessary to minimize the impact of circadian misalignment on health.
Journal Article
Rhythmic aspects of behavior
This text provides rich evidence of the relevance of the temporal aspects of behaviour. The generalized areas of learning, memory, operant scheduled behaviour, task performance, vigilance, mood and motivation and their rhythmic components are explored in varying detail. The particularized measures range from on-the-job errors, through reading efficiency to milliseconds of change in reaction time in the laboratory. The subjects range from ants to older persons. Across this range of settings, subjects, and behaviours, the message is clear: there is an interaction between time and behaviour.
Book
Physiological Rhythms and Biological Variation of Biomolecules: The Road to Personalized Laboratory Medicine
The concentration of biomolecules in living systems shows numerous systematic and random variations. Systematic variations can be classified based on the frequency of variations as ultradian (<24 h), circadian (approximately 24 h), and infradian (>24 h), which are partly predictable. Random biological variations are known as between-subject biological variations that are the variations among the set points of an analyte from different individuals and within-subject biological variation, which is the variation of the analyte around individuals’ set points. The random biological variation cannot be predicted but can be estimated using appropriate measurement and statistical procedures. Physiological rhythms and random biological variation of the analytes could be considered the essential elements of predictive, preventive, and particularly personalized laboratory medicine. This systematic review aims to summarize research that have been done about the types of physiological rhythms, biological variations, and their effects on laboratory tests. We have searched the PubMed and Web of Science databases for biological variation and physiological rhythm articles in English without time restrictions with the terms “Biological variation, Within-subject biological variation, Between-subject biological variation, Physiological rhythms, Ultradian rhythms, Circadian rhythm, Infradian rhythms”. It was concluded that, for effective management of predicting, preventing, and personalizing medicine, which is based on the safe and valid interpretation of patients’ laboratory test results, both physiological rhythms and biological variation of the measurands should be considered simultaneously.
Journal Article