scholarly journals Light Exposure Patterns in Healthy Older and Young Adults

2010 ◽  
Vol 25 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Karine Scheuermaier ◽  
Alison M. Laffan ◽  
Jeanne F. Duffy
2021 ◽  
Vol 12 ◽  
Author(s):  
Danilo E. F. L. Flôres ◽  
Milene G. Jannetti ◽  
Giovane C. Improta ◽  
Patricia Tachinardi ◽  
Veronica S. Valentinuzzi ◽  
...  

Living organisms anticipate the seasons by tracking the proportion of light and darkness hours within a day—photoperiod. The limits of photoperiod measurement can be investigated in the subterranean rodents tuco-tucos (Ctenomys aff. knighti), which inhabit dark underground tunnels. Their exposure to light is sporadic and, remarkably, results from their own behavior of surface emergence. Thus, we investigated the endogenous and exogenous regulation of this behavior and its consequences to photoperiod measurement. In the field, animals carrying biologgers displayed seasonal patterns of daily surface emergence, exogenously modulated by temperature. In the laboratory, experiments with constant lighting conditions revealed the endogenous regulation of seasonal activity by the circadian clock, which has a multi-oscillatory structure. Finally, mathematical modeling corroborated that tuco-tuco’s light exposure across the seasons is sufficient for photoperiod encoding. Together, our results elucidate the interrelationship between the circadian clock and temperature in shaping seasonal light exposure patterns that convey photoperiod information in an extreme photic environment.


2021 ◽  
pp. bjophthalmol-2021-318918
Author(s):  
Mijie Li ◽  
Carla Lanca ◽  
Chuen-Seng Tan ◽  
Li-Lian Foo ◽  
Chen-Hsin Sun ◽  
...  

Background/aimsTo evaluate the association of reported time outdoors and light exposure patterns with myopia among children aged 9 years from the Growing Up in Singapore Towards Healthy Outcomes birth cohort.MethodsWe assessed reported time outdoors (min/day), light exposure patterns and outdoor activities of children aged 9 years (n=483) with a questionnaire, the FitSight watch and a 7-day activity diary. Light levels, the duration, timing and frequency of light exposure were assessed. Cycloplegic spherical equivalent (SE), myopia (SE≤−0.5 D) and axial length (AL) of paired eyes were analysed using generalised estimating equations.ResultsIn this study, 483 (966 eyes) multiethnic children (50.0% boys, 59.8% Chinese, 42.2% myopic) were included. Reported time outdoors (mean±SD) was 100±93 min/day, and average light levels were 458±228 lux. Of the total duration children spent at light levels of ≥1000 lux (37±19 min/day), 76% were spent below 5000 lux. Peak light exposure occurred at mid-day. Children had 1.7±1.0 light exposure episodes/day. Common outdoor activities were walks, neighbourhood play and swimming. Greater reported time outdoors was associated with lower odds of myopia (OR=0.82, 95% CI 0.70 to 0.95/hour increase daily; p=0.009). Light levels, timing and frequency of light exposures were not associated with myopia, SE or AL (p>0.05).ConclusionReported time outdoors, light levels and number of light exposure episodes were low among Singaporean children aged 9 years. Reported time outdoors was protective against myopia but not light levels or specific light measures. A multipronged approach to increase time outdoors is recommended in the combat against the myopia epidemic.


Circulation ◽  
2017 ◽  
Vol 135 (suppl_1) ◽  
Author(s):  
Donald M Lloyd-Jones ◽  
Laura Colangelo ◽  
Beth Lewis ◽  
Pamela Schreiner ◽  
Stephen Sidney ◽  
...  

Background: Data are sparse regarding associations of risk factors (RF) across young adulthood with development of adverse left ventricular (LV) structure and function by middle age, and it is unclear whether baseline, cumulative, or longitudinal RF exposure patterns best represent that risk. Methods: We included up to 2335 CARDIA participants (ppts) who had echocardiographic data from exam year (Y)5, Y25, and Y30, and RF data from at least 3 exams including Y0 and Y25. Echo outcomes included Y30 indexed LV end-systolic (ESD/ht) and -diastolic (EDD/ht) dimensions, and LV mass (M/ht 2.7 ), septal and posterior wall thickness, ejection fraction (EF), and incident adverse geometry (defined as LV concentric remodeling [CR], concentric hypertrophy [cLVH], or eccentric hypertrophy [eLVH]). We used multivariable linear, logistic or polytomous regression (as appropriate to endpoint) to examine associations of RF exposures measured as: 1) baseline (Y0); 2) change from Y0 to Y25; 3) cumulative exposure from Y0 to Y25 (e.g., pack-yrs, mmHg-yrs); or 4) latent class trajectories (using PROC TRAJ) from Y0 to Y25, with adjustment for demographics and relevant Y5 echo measures. Results: At Y30, ppts were 55±4 yrs, 56% women and 44% black; 12% smoked, mean BMI was 30.4±7, 37% had hypertension, and 17% diabetes; 20.5% had incident LVH; 4.5% EF<50%; and 37.2% adverse LV geometry. Models representing cumulative RF exposures tended to have the highest adjusted R 2 and lowest AIC for continuous and categorical Y30 LV outcomes. The table shows associations of cumulative RFs from Y0 to Y25 with incident LVH, EF<50%, and adverse LV geometry at Y30. Few RFs were consistently associated with Y25-Y30 change in echo measures, but they included education and SBP. Conclusions: Among initially healthy young adults, cumulative risk factor exposures (often within clinically normative ranges) over 25 years are significantly associated with continuous LV echo measures and adverse LV outcomes by middle age, suggesting the importance of primordial prevention.


2019 ◽  
Vol 3 ◽  
pp. 170-171
Author(s):  
Huss A ◽  
van Wel L ◽  
Bogaards L ◽  
Vrijkotte T ◽  
Vermeulen R

1990 ◽  
Vol 15 (3) ◽  
pp. 193-205 ◽  
Author(s):  
M. Clodoré ◽  
J. Foret ◽  
O. Benoit ◽  
Y. Touitou ◽  
A. Aguirre ◽  
...  

2021 ◽  
Vol 2042 (1) ◽  
pp. 012111
Author(s):  
Mariëlle P.J. Aarts ◽  
Steffen L. Hartmeyer ◽  
Kars Morsink ◽  
Helianthe S.M. Kort

Abstract Nightshift work can negatively impact sleep, performance, and health. Careful manipulation of light exposure patterns can help reduce these negative effects but is challenging in conditions of rapidly rotating shiftwork and due to individual differences. As chronotype is related to shiftwork tolerance, we explored patterns of sleep, sleepiness, and light exposure during the first day of nightshift work between earlier and later chronotypes, based on data from an observational field study among rapidly rotating hospital nurses. Due to the limited sample size, only descriptive analyses and visual inspection were conducted. In line with findings of lower shiftwork tolerance, earlier chronotypes (N=6) seemed to be sleepier during work and sleep less than later types (N=7). Differences were also observed in light exposure patterns, revealing potential for light exposure interventions, and suggesting a contribution to shiftwork tolerance. For future intervention studies in aiming to identify a light exposure strategy, our findings highlight the importance of investigating light exposure relative to the individual circadian phase.


2019 ◽  
Vol 64 ◽  
pp. S355
Author(s):  
A. Skeldon ◽  
N. Santhi ◽  
T. Shochat ◽  
S. Flavell ◽  
D.-J. Dijk

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