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3 pages, 178 KiB

Open AccessEditorial

Special Issue on “Research on Circadian Rhythms in Health and Disease”

by Denis Gubin, Germaine Cornelissen, Oliver Stefani and Dietmar Weinert

Appl. Sci. 2023, 13(19), 10728; https://doi.org/10.3390/app131910728 - 27 Sep 2023

Viewed by 1093

Abstract

Despite rigorous investigation of circadian rhythms in humans and animal models in the past, basic chronobiologic principles have not yet entered clinical practice [...] Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

Research

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12 pages, 1292 KiB

Open AccessArticle

Method to Calculate Melanopic Light Reaching the Retina Depending on the Optical Density of an Aging Crystalline Lens

by Ana Sanchez-Cano, Elvira Orduna-Hospital, Guisela Fernández-Espinosa and Justiniano Aporta

Appl. Sci. 2023, 13(4), 2569; https://doi.org/10.3390/app13042569 - 16 Feb 2023

Cited by 1 | Viewed by 2061

Abstract

Lighting studies that take into account the age of the inhabitants of an area and are related to circadian light are difficult to find. This study aims to simplify a method to approximately compute the circadian light reaching the retina based on photopic [...] Read more.

Lighting studies that take into account the age of the inhabitants of an area and are related to circadian light are difficult to find. This study aims to simplify a method to approximately compute the circadian light reaching the retina based on photopic illuminance reaching the corneal plane and considering the optical density of an aging crystalline lens. As an example of this proposed method, calculations were performed with both the D65 and A standard illuminants, showing how the spectral power distribution is modified by the optical density of the crystalline lens, mainly at short wavelengths. Due to these selective wavelength absorptions of the aged lens, a significant variation in the level of daylight equivalent melanopic illuminance (EDI) is present in the retina. With levels of 200 lux at the corneal plane, these variations ranged from 204 EDI lux to 178 EDI lux for the D65 standard illuminant, and from 99 EDI lux to 101 EDI lux for the A standard illuminant for observers aged 10 and 90, respectively. In this work, we aimed to simplify the greatest possible level of calculation of melanopic light, while describing simple protocols that are easy to translate into practice. Our results will allow researchers to carry out optimized lighting designs from both the photometric and circadian perspectives considering the optical density of an aging lens. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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19 pages, 1674 KiB

Open AccessFeature PaperArticle

Rules of Heliogeomagnetics Diversely Coordinating Biological Rhythms and Promoting Human Health

by Kuniaki Otsuka, Germaine Cornelissen, Andi Weydahl, Denis Gubin, Larry A. Beaty and Masatoshi Murase

Appl. Sci. 2023, 13(2), 951; https://doi.org/10.3390/app13020951 - 10 Jan 2023

Cited by 2 | Viewed by 2253

Abstract

This investigation reviews how geomagnetic activity affects the circadian variation in blood pressure (BP) and heart rate (HR) and their variabilities of clinically healthy individuals. A small study in Alta, Norway (latitude of 70.0° N), serves to illustrate the methodology used to outline [...] Read more.

This investigation reviews how geomagnetic activity affects the circadian variation in blood pressure (BP) and heart rate (HR) and their variabilities of clinically healthy individuals. A small study in Alta, Norway (latitude of 70.0° N), serves to illustrate the methodology used to outline rules of procedure in exploring heliogeomagnetic effects on human physiology. Volunteers in the Alta study were monitored for at least 2 days between 18 March 2002 and 9 January 2005. Estimates of the circadian characteristics of BP and HR by cosinor and the Maximum Entropy Method (MEM) indicate an increase in the circadian amplitude of systolic (S) BP on geomagnetic-disturbance days compared to quiet days (p = 0.0236). Geomagnetic stimulation was found to be circadian-phase dependent, with stimulation in the evening inducing a 49.2% increase in the circadian amplitude of SBP (p = 0.0003), not observed in relation to stimulation in the morning. In two participants monitored for 7 days, the circadian amplitude of SBP decreased by 23.4% on an extremely disturbed day but increased by 50.3% on moderately disturbed days (p = 0.0044), suggesting a biphasic (hormetic) reaction of the circadian SBP rhythm to geomagnetics. These results indicate a possible role of geomagnetic fluctuations in modulating the circadian system. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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17 pages, 1817 KiB

Open AccessArticle

The Irrecoverable Loss in Sleep on Weekdays of Two Distinct Chronotypes Can Be Equalized by Permitting a >2 h Difference in Waking Time

by Arcady A. Putilov, Dmitry S. Sveshnikov, Zarina V. Bakaeva, Elena B. Yakunina, Yuri P. Starshinov, Vladimir I. Torshin, Elena A. Trutneva, Michael M. Lapkin, Zhanna N. Lopatskaya, Roman O. Budkevich, Elena V. Budkevich, Elena L. Tinkova, Marina P. Dyakovich, Larisa P. Cherapkina, Olga G. Donskaya, Alexandra N. Puchkova and Vladimir B. Dorokhov

Appl. Sci. 2022, 12(16), 8092; https://doi.org/10.3390/app12168092 - 12 Aug 2022

Cited by 3 | Viewed by 1636

Abstract

Background: Our work/study culture is biased towards the circadian clocks of “morning types”, whereas “evening types” are forced to advance their weekday waking times relative to weekend waking times. Since the experimental research consistently reveals a >2 h difference between these two chronotypes [...] Read more.

Background: Our work/study culture is biased towards the circadian clocks of “morning types”, whereas “evening types” are forced to advance their weekday waking times relative to weekend waking times. Since the experimental research consistently reveals a >2 h difference between these two chronotypes in the positions of their endogenous circadian phases, we hypothesized the necessity to permit a >2 h difference between them in weekday waking times to equalize their irrecoverable loss in sleep on weekdays. Methods: A total of 659 and 1106 participants of online surveys identified themselves as morning and evening types, respectively. The hypothesis was tested by applying a model of sleep–wake regulation for simulating sleep times reported by 245 lecturers of these two types, and by comparison of sleep times of these types among these lecturers and 1520 students. Results: The hypothesis was supported by results showing that, if, on weekdays, an “average” morning type wakes at 6 a.m., the equalization of the weekday sleep loss of the two chronotypes would require the waking time of an “average” evening type to be no earlier than 8 a.m. Conclusions: These results may be implemented in a model-based methodology for the correction of weekday waking times to equalize weekday sleep loss. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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12 pages, 1188 KiB

Open AccessArticle

Actimetry-Derived 24 h Rest–Activity Rhythm Indices Applied to Predict MCTQ and PSQI

by Mikhail Borisenkov, Tatyana Tserne, Larisa Bakutova and Denis Gubin

Appl. Sci. 2022, 12(14), 6888; https://doi.org/10.3390/app12146888 - 7 Jul 2022

Cited by 4 | Viewed by 1723

Abstract

The aim of this study was to identify wrist actimetry-based indices associated with the sleep–wake rhythm characteristics of healthy individuals. The study involved 79 healthy subjects of both sexes (age range 15–62 years (mean: 21.5 ± 9.6 years, women: 77.8%)). Each participant provided [...] Read more.

The aim of this study was to identify wrist actimetry-based indices associated with the sleep–wake rhythm characteristics of healthy individuals. The study involved 79 healthy subjects of both sexes (age range 15–62 years (mean: 21.5 ± 9.6 years, women: 77.8%)). Each participant provided personal data, filled out two questionnaires, the Munich ChronoType Questionnaire (MCTQ) and the Pittsburgh Sleep Quality Index (PSQI), and wore a wrist actimeter for a week. A significant positive association of the chronotype with the mid-phase of the most active 10 h period (M10t: B = 0.252, p = 0.015), the mid-phase of the least active 5 h period (L5t: B = 0.338, p = 0.005), and the interdaily stability (IS: B = −0.021, p = 0.017) was noted, as well as the sleep duration with the M10t (B = −0.257, p = 0.003), L5t (B = −0.340, p = 0.001), and IS (B = 0.042, p = 0.003). There was a significant association of social jetlag (B = 0.320, p = 0.032) and sleep quality (B = 0.990, p = 0.013) with motor activity in bed, as well as sleep efficiency with the acrophase (B = −0.043, p = 0.007). Nonparametric indices of the 24 h rest–activity rhythm are useful tools for assessing the sleep–wake rhythm of healthy individuals. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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15 pages, 3176 KiB

Open AccessArticle

Daytime Lipid Metabolism Modulated by CLOCK Gene Is Linked to Retinal Ganglion Cells Damage in Glaucoma

by Denis Gubin, Vladimir Neroev, Tatyana Malishevskaya, Sergey Kolomeichuk, Dietmar Weinert, Natalya Yuzhakova, Alsu Nelaeva, Yulia Filippova and Germaine Cornelissen

Appl. Sci. 2022, 12(13), 6374; https://doi.org/10.3390/app12136374 - 23 Jun 2022

Cited by 4 | Viewed by 2115

Abstract

Lipid metabolism is intimately linked to circadian mechanisms and light signaling. Deteriorated photic transduction because of retinal ganglion cell (RGC) loss occurring with glaucoma progression reduces perceived light amplitude, causing circadian disruption. To investigate associations with RGCs, total cholesterol (TC), its low-density (LDL-C) [...] Read more.

Lipid metabolism is intimately linked to circadian mechanisms and light signaling. Deteriorated photic transduction because of retinal ganglion cell (RGC) loss occurring with glaucoma progression reduces perceived light amplitude, causing circadian disruption. To investigate associations with RGCs, total cholesterol (TC), its low-density (LDL-C) and high-density (HDL-C) fractions, and triglycerides (TG) were measured, under a controlled meal regimen, during daytime hours in 114 patients diagnosed with primary open-angle glaucoma (POAG). RGC damage was assessed by high-definition optical coherence tomography (HD-OCT). Analysis of eight clock, clock-related, and melatonin receptor gene polymorphisms was performed on 19 patients. RGC loss was associated with changes in lipid metabolism in a time-dependent manner. Morning (08:00) values of HDL-C (r = 0.613, p < 0.0001) and TG (r = 0.568, p < 0.0001) correlated positively with RGC global loss, while LDL-C at 08:00 had a weak correlation (r = 0.235; p = 0.012) but showed a strong correlation in the evening (20:00) (r = 0.533, p < 0.0001). The morning–evening gradients (MEGs, changes at 20:00 versus 08:00) in TC and LDL-C changed sign from a negative to a positive association in patients exceeding the 15% two-eye mean GLV threshold. MEG (LDL-C higher in the evening than in the morning) was positive only in POAG patients with the CLOCK_3111 TT genotype. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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7 pages, 240 KiB

Open AccessArticle

A Closer Look at the Sleep/Wake Habits and Dark Triad Traits

by Arash Rahafar, Lisa Sophie Kalbacher and Christoph Randler

Appl. Sci. 2022, 12(12), 5963; https://doi.org/10.3390/app12125963 - 11 Jun 2022

Cited by 4 | Viewed by 1915

Abstract

In this study, we sought to explore the association between sleep/wake habits and the Dark Triad (DT) traits. The sample consisted of 637 university students who filled out the measures of the Dark Triad, sleep quality, daytime sleepiness, and sleep timing. There was [...] Read more.

In this study, we sought to explore the association between sleep/wake habits and the Dark Triad (DT) traits. The sample consisted of 637 university students who filled out the measures of the Dark Triad, sleep quality, daytime sleepiness, and sleep timing. There was a positive relationship between the Dark Triad composite and eveningness, and a negative relationship between the DT and circadian distinctness was observed. Psychopathy appeared as the most sleep-related DT trait, and narcissism appeared as the least sleep-related one. Psychopathy and Machiavellianism predicted bedtime prior to free days stronger than the other sleep variables. This study suggests that both sleep timing and sleep stability are influenced by higher DT traits. As sleep disturbances go along with some other comorbid mental problems, looking for the possible underlying factors such as biological markers or psychological traits is warranted. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

Review

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14 pages, 1560 KiB

Open AccessReview

Wearable Light-and-Motion Dataloggers for Sleep/Wake Research: A Review

by Konstantin V. Danilenko, Oliver Stefani, Kirill A. Voronin, Marina S. Mezhakova, Ivan M. Petrov, Mikhail F. Borisenkov, Aleksandr A. Markov and Denis G. Gubin

Appl. Sci. 2022, 12(22), 11794; https://doi.org/10.3390/app122211794 - 20 Nov 2022

Cited by 3 | Viewed by 4267

Abstract

Long-term recording of a person’s activity (actimetry or actigraphy) using devices typically worn on the wrist is increasingly applied in sleep/wake, chronobiological, and clinical research to estimate parameters of sleep and sleep-wake cycles. With the recognition of the importance of light in influencing [...] Read more.

Long-term recording of a person’s activity (actimetry or actigraphy) using devices typically worn on the wrist is increasingly applied in sleep/wake, chronobiological, and clinical research to estimate parameters of sleep and sleep-wake cycles. With the recognition of the importance of light in influencing these parameters and with the development of technological capabilities, light sensors have been introduced into devices to correlate physiological and environmental changes. Over the past two decades, many such new devices have appeared from different manufacturers. One of the aims of this review is to help researchers and clinicians choose the data logger that best fits their research goals. Seventeen currently available light-and-motion recorders entered the analysis. They were reviewed for appearance, dimensions, weight, mounting, battery, sensors, features, communication interface, and software. We found that all devices differed from each other in several features. In particular, six devices are equipped with a light sensor that can measure blue light. It is noteworthy that blue light most profoundly influences the physiology and behavior of mammals. As the wearables market is growing rapidly, this review helps guide future developments and needs to be updated every few years. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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12 pages, 669 KiB

Open AccessReview

The Impact of Physical Activity on the Circadian System: Benefits for Health, Performance and Wellbeing

by Dietmar Weinert and Denis Gubin

Appl. Sci. 2022, 12(18), 9220; https://doi.org/10.3390/app12189220 - 14 Sep 2022

Cited by 16 | Viewed by 5606

Abstract

Circadian rhythms are an inherent property of all living systems and an essential part of the external and internal temporal order. They enable organisms to be synchronized with their periodic environment and guarantee the optimal functioning of organisms. Any disturbances, so-called circadian disruptions, [...] Read more.

Circadian rhythms are an inherent property of all living systems and an essential part of the external and internal temporal order. They enable organisms to be synchronized with their periodic environment and guarantee the optimal functioning of organisms. Any disturbances, so-called circadian disruptions, may have adverse consequences for health, physical and mental performance, and wellbeing. The environmental light–dark cycle is the main zeitgeber for circadian rhythms. Moreover, regular physical activity is most useful. Not only does it have general favorable effects on the cardiovascular system, the energy metabolism and mental health, for example, but it may also stabilize the circadian system via feedback effects on the suprachiasmatic nuclei (SCN), the main circadian pacemaker. Regular physical activity helps to maintain high-amplitude circadian rhythms, particularly of clock gene expression in the SCN. It promotes their entrainment to external periodicities and improves the internal synchronization of various circadian rhythms. This in turn promotes health and wellbeing. In experiments on Djungarian hamsters, voluntary access to a running wheel not only stabilized the circadian activity rhythm, but intensive wheel running even reestablished the rhythm in arrhythmic individuals. Moreover, their cognitive abilities were restored. Djungarian hamsters of the arrhythmic phenotype in which the SCN do not generate a circadian signal not only have a diminished cognitive performance, but their social memory is also compromised. Voluntary wheel running restored these abilities simultaneously with the reestablishment of the circadian activity rhythm. Intensively exercising Syrian hamsters are less anxious, more resilient to social defeat, and show less defensive/submissive behaviors, i.e., voluntary exercise may promote self-confidence. Similar effects were described for humans. The aim of the present paper is to summarize the current knowledge concerning the effects of physical activity on the stability of the circadian system and the corresponding consequences for physical and mental performance. Full article

(This article belongs to the Special Issue Research on Circadian Rhythms in Health and Disease)

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