scholarly journals Weekly and seasonal variation in the circadian melatonin rhythm in humans: entrained to local clock time, social time, light exposure or sun time?

2021 ◽  
Author(s):  
Anne C Skeldon ◽  
Derk‐Jan Dijk
Keyword(s):  
Seasonal Variation ◽  
Light Exposure ◽  
Clock Time ◽  
Melatonin Rhythm ◽  
Local Clock ◽  
Social Time

Seasonal variation in dormancy and light sensitivity in buried seeds of eight annual weed species

1997 ◽  
Vol 75 (11) ◽  
pp. 1998-2004 ◽  
Author(s):  
Per Milberg ◽  
Lars Andersson
Keyword(s):  
Seasonal Variation ◽  
Seasonal Changes ◽  
Light Exposure ◽  
Light Sensitivity ◽  
Light Treatment ◽  
Weed Species ◽  
Light Requirement ◽  
Papaver Rhoeas ◽  
Buried Seeds ◽  
Urtica Urens

We recorded germination in three different light environments (light, dark, and after a short light exposure) in eight annual weed species. Seeds were buried outdoors at the end of November 1994 and exhumed monthly from March 1995 to April 1996. All species exhibited substantial seasonal changes in dormancy level, and the patterns suggest that seeds of Papaver rhoeas germinate strictly in the autumn; Capsella bursa-pastoris, Descurainia sophia, Spergula arvensis, and Urtica urens mainly in the autumn; Chenopodium suecicum strictly in the spring; and Matricaria perforata mainly in the spring. Lapsana communis showed inconsistent dormancy changes over the year. All species had acquired a light requirement for germination after being in the soil, and in many cases the short light exposure (1050 μmol∙m−2) was enough to fulfil this requirement. The demonstrated seasonal changes in light sensitivity in several of the species will have to be taken into account in attempts to photocontrol weeds. By using the short-light treatment, we were able to detect seasonal dormancy changes that would not have been obvious by testing for germination in only light and darkness. Hence, light is not a simple dichotomous factor in its effect on germination. Key words: dormancy, germination, light, seed, Sweden, weed.

Vitamin B12 enhances the phase-response of circadian melatonin rhythm to a single bright light exposure in humans

1996 ◽  
Vol 220 (2) ◽  
pp. 129-132 ◽  
Author(s):  
Satoko Hashimoto ◽  
Masako Kohsaka ◽  
Nobuyuki Morita ◽  
Noriko Fukuda ◽  
Sato Honma ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Light Exposure ◽  
Bright Light ◽  
Phase Response ◽  
Melatonin Rhythm ◽  
Bright Light Exposure

scholarly journals Characterizing the Modern Light Environment and its Influence on Circadian Rhythms

2020 ◽  
Author(s):  
Dennis Khodasevich ◽  
Susan Tsui ◽  
Darwin Keung ◽  
Debra J. Skene ◽  
Micaela E. Martinez
Keyword(s):  
Seasonal Variation ◽  
Circadian Rhythms ◽  
General Population ◽  
Light Exposure ◽  
Circadian Disruption ◽  
Natural Light ◽  
Light Sources ◽  
Four Seasons ◽  
Nighttime Light ◽  
The Impact

AbstractHumans have largely supplanted natural light cycles with a variety of artificial light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. We measured light exposure and wrist temperature among residents of New York City for a full week during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, for all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modeled the impact of morning, afternoon, and nighttime light exposure on the timing of the midline-estimating statistic of rhythm (MESOR). We found that morning light exposure and nighttime light exposure had a significant but opposing impact on MESOR timing. Our results demonstrate that nighttime light can shift/alter circadian rhythms to delay the morning transition from nighttime to daytime physiology, while morning light can lead to earlier onset. Our results demonstrate that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized. Due to the impact of circadian rhythms on health, this is convincing evidence that real-world monitoring of light exposure and circadian rhythms could lead to new advances in personalized medicine.Significance StatementDisruption of circadian rhythms has been linked to various diseases, but the prevalence of circadian disruption among the general population is unknown. Light plays a pivotal role in entraining circadian rhythms to the 24-hour day. Humans have largely supplanted natural light cycles with a variety of electric light sources and by spending large amounts of time indoors. We have shown that individuals experience a pronounced disconnect from natural light cycles. This disconnect includes low daytime light exposure, high levels of light-at-night, and minimal seasonal variation in light exposure. We identified measurable changes in wrist temperature rhythms as a function of differential light exposure during the morning and nighttime hours. Our findings suggest that circadian shifts, and even disruption, may be common in the general population.

Seasonal Variation in Migraine

Cephalalgia ◽  
2005 ◽  
Vol 25 (10) ◽  
pp. 811-816 ◽  
Author(s):  
KB Alstadhaug ◽  
R Salvesen ◽  
SI Bekkelund
Keyword(s):  
Seasonal Variation ◽  
Sleep Disturbances ◽  
Light Exposure ◽  
Light Conditions ◽  
Circadian Variations ◽  
Polar Night ◽  
Seasonal Periodicity ◽  
Frequent Use ◽  
Arctic Area ◽  
The Impact

Our group has previously shown that migraineurs, as opposed to individuals with other headaches, are more likely to have headache during the bright arctic summer than during the polar night season. We set out to investigate the impact of seasonal light exposure in migraine with and without aura. We performed a questionnaire-based study of 169 female volunteer migraineurs in an arctic area where light conditions during summer and winter seasons are extreme. We included 98 patients with migraine with aura (MA) and 71 with migraine without aura (MoA). One hundred and seven patients (63%) reported seasonal variation in migraine attack frequency. Close to half (47%) of patients with aura, but only 17% of patients without aura, reported more frequent attacks during the light season ( P < 0.001). Patients with MA reported interictal light hypersensitivity and light exposure as an attack precipitating factor significantly more often than individuals with MoA. They also reported significantly more frequent use of sunglasses to prevent attacks. We found no significant differences between MA and MoA as regards sleep disturbances, use of oral contraceptives, impact of headache or circadian variations. Seasonal periodicity of migraine in an arctic population with more frequent attacks during the light season is a convincing phenomenon in MA but not in MoA. The amount of light exposure seems to be pivotal to this variation.

scholarly journals Protecting the Melatonin Rhythm through Circadian Healthy Light Exposure

2014 ◽  
Vol 15 (12) ◽  
pp. 23448-23500 ◽  
Author(s):  
Maria Bonmati-Carrion ◽  
Raquel Arguelles-Prieto ◽  
Maria Martinez-Madrid ◽  
Russel Reiter ◽  
Ruediger Hardeland ◽  
...  
Keyword(s):  
Light Exposure ◽  
Melatonin Rhythm

scholarly journals High Sensitivity of the Human Circadian Melatonin Rhythm to Resetting by Short Wavelength Light

2003 ◽  
Vol 88 (9) ◽  
pp. 4502-4505 ◽  
Author(s):  
Steven W. Lockley ◽  
George C. Brainard ◽  
Charles A. Czeisler
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Monochromatic Light ◽  
High Sensitivity ◽  
Photon Density ◽  
Retinal Ganglion ◽  
Circadian Pacemaker ◽  
Melatonin Rhythm ◽  
Circadian Phase ◽  
Short Wavelength Light

The endogenous circadian oscillator in mammals, situated in the suprachiasmatic nuclei, receives environmental photic input from specialized subsets of photoreceptive retinal ganglion cells. The human circadian pacemaker is exquisitely sensitive to ocular light exposure, even in some people who are otherwise totally blind. The magnitude of the resetting response to white light depends on the timing, intensity, duration, number and pattern of exposures. We report here that the circadian resetting response in humans, as measured by the pineal melatonin rhythm, is also wavelength dependent. Exposure to 6.5 h of monochromatic light at 460 nm induces a two-fold greater circadian phase delay than 6.5 h of 555 nm monochromatic light of equal photon density. Similarly, 460 nm monochromatic light causes twice the amount of melatonin suppression compared to 555 nm monochromatic light, and is dependent on the duration of exposure in addition to wavelength. These studies demonstrate that the peak of sensitivity of the human circadian pacemaker to light is blue-shifted relative to the three-cone visual photopic system, the sensitivity of which peaks at ∼555 nm. Thus photopic lux, the standard unit of illuminance, is inappropriate when quantifying the photic drive required to reset the human circadian pacemaker.

Seasonal variation and alcohol consumption: A retrospective observational study

2017 ◽  
Vol 41 (S1) ◽  
pp. s874-s874 ◽  
Author(s):  
R.A. Colombo ◽  
M. Preve ◽  
E. Bolla ◽  
R. Traber
Keyword(s):  
Seasonal Variation ◽  
Alcohol Consumption ◽  
Mood Disorders ◽  
Light Exposure ◽  
Alcohol Intoxication ◽  
Alcohol Exposure ◽  
Co Morbidity ◽  
Significant Difference ◽  
Axis I ◽  
And Behavior

IntroductionSeasonal and geographic variations in light exposure influence human mood and behavior, including alcohol consumption. In literature alcohol consumption have a clear seasonal rhythm, with specific differences during the year . Seasonal changes in mood and behavior (seasonality) may be closely related to alcoholism. The aim of our study is to evaluate the relationship between alcohol consumption and seasonal variation.MethodOne hundred and nine inpatient are assessed with: the SCID-P for axis I diagnosis. Inclusion criteria are: (1) acute alcohol intoxication at the admission. All the socio-demographic characteristics are explained.ResultsThe peak period of alcohol admission is in the autumn, the lowest period is in spring in April and May. There is any significant difference related to gender. The 76% of the admission are coerced admission. The rates of co-morbidity are: personality disorders (30.3%), affective disorders (22.9%) and psychotic disorders (12.8%).Discussion and conclusionSome patients with alcoholism have a seasonal pattern to their alcohol misuse. Several lines of evidence suggest that changes in the circadian system are also involved in the development of non-seasonal mood disorders, such as major depression and bipolar disorder. Thus, developmental alcohol exposure produces subtle abnormalities in circadian rhythms that may contribute to the development of seasonal and non-seasonal mood disorders. Further research is warranted to replicate our clinical and qualitative observations and, in general, quantitative studies in large samples followed up over time are needed. Methodological limitations, clinical implications and suggestions for future research directions are considered.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Melatonin rhythm is not shifted by lights that suppress nocturnal melatonin in humans under entrainment

1996 ◽  
Vol 270 (5) ◽  
pp. R1073-R1077 ◽  
Author(s):  
S. Hashimoto ◽  
K. Nakamura ◽  
S. Honma ◽  
H. Tokura ◽  
K. Honma
Keyword(s):  
Light Intensity ◽  
Light Exposure ◽  
Early Morning ◽  
The Other ◽  
Melatonin Level ◽  
Young Males ◽  
Melatonin Rhythm ◽  
Other Hand ◽  
The One ◽  
The Relationship

Effects of a single light exposure on the circadian rhythm in plasma melatonin were, examined in young males to obtain the threshold of light intensity for suppressing the nocturnal melatonin level on the one hand and to understand the relationship between the light-induced phase shift of melatonin rhythm and the melatonin suppression on the other hand. Eight subjects spent 3 days in an experimental living facility where light intensity was set below 200 lx and were exposed to light for 3 h in the early morning on the 2nd day. The same procedure was repeated five times in each subject with an interval of at least 3 wk, and one of five light intensities was tested in each trial. As a result, nocturnal melatonin level was not suppressed by light of 200 lx but significantly suppressed by light of intensity > or + 500 lx. On the other hand, the circadian melatonin rhythm was not shifted by any light intensity up to 10,000 lx. It is concluded that the threshold of light intensity for suppressing the melatonin level is located between 200 and 500 lx in young Japanese males, and the threshold for phase shifting the circadian melatonin rhythm was much greater than that for suppressing the nocturnal melatonin level in humans under entrained conditions.

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