Browsing by Subject "Light exposure"

Now showing 1 - 4 of 4
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    Assessing Chronotypes by Ambulatory Circadian Monitoring
    (Frontiers Media, 2019-11-20) Martinez-Nicolas, A; Martinez-Madrid, M J; Almaida Pagán, Pedro Francisco; Madrid, Juan A; Rol, M A; Bonmatí Carrión, María de los Ángeles; Fisiología; Chronobiology Lab, Department of Physiology, College of Biology, University of Murcia, Mare Nostrum Campus, IUIE, IMIB-Arrixaca, Murcia, Spain; Ciber Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
    In order to develop objective indexes for chronotype identification by means of direct measurement of circadian rhythms, 159 undergraduate students were recruited as volunteers and instructed to wear ambulatory circadian monitoring (ACM) sensors that continuously gathered information on the individual’s environmental light and temperature exposure, wrist temperature, body position, activity, and the integrated TAP (temperature, activity, and position) variable for 7 consecutive days under regular freeliving conditions. Among all the proposed indexes, the night phase marker (NPM) of the TAP variable was the best suited to discriminate among chronotypes, due to its relationship with the Munich ChronoType Questionnaire (b = 0.531; p < 0.001). The NPM of TAP allowed subjects to be classified as early- (E-type, 20%), neither- (N-type, 60%), and late-types (L-type, 20%), each of which had its own characteristics. In terms of light exposure, while all subjects had short exposure times to bright light (>100 lux), with a daily average of 93.84 5.72 min, the earlier chronotypes were exposed to brighter days and darker nights compared to the later chronotypes. Furthermore, the earlier chronotypes were associated with higher stability and day–night contrast, along with an earlier phase, which could be the cause or consequence of the light exposure habits. Overall, these data support the use of ACM for chronotype identification and for evaluation under free living conditions, using objective markers.
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    Correction: Circadian system functional status and sleep in blind subjects with and without conscious light perception
    (Frontiers Media, 2026-04-13) Martínez Martínez, David; González Romero, Pedro; Rodríguez Morilla, Beatriz; Bonmatí Carrión, María de los Ángeles; Rol de Lama, María de los Ángeles; Almaida Pagán, Pedro Francisco; Fisiología; Facultades de la UMU::Facultad de Biología
    To understand circadian rhythms and sleep in an understudied population, which is particularly prone to suffer chronodisruption (CD), eighteen blind volunteers of 51.5 ± 3.6 years (Mean ± SEM) and 26 volunteers (51.8 ± 1.2) with no visual impairments wore the ambulatory circadian monitoring (ACM) device Kronowise® for seven consecutive days in real-life conditions. Nine of the blind participants declared to have some sort of light perception while the other nine declared to lack conscious light perception. ACM combines measurements of distal skin temperature; motor activity, light exposure and feeding schedules, providing information about lifestyle and the bidirectional crosstalk between internal time and external synchronisers, which is paramount to determine a subject’s CD degree. We found a extraordinarily diverse population in terms of blindness aetiology and thus, in the degree of affectation of the participants visual and circadian systems. Our results pointed to poorer circadian health and sleep in the blind participants, which could be directly related to the impact of disease over circadian photoreception but also to disruption of daily habits. Compared to controls, blind participants showed significantly lower light exposure and physical activity values during the day and higher time of movement during the night. Besides, we analysed feeding schedules in the blind participants for the first time and found that their last meal of the day happened later than in controls, thus blind participants’ night fasting was shorter. Altogether, our results indicated substantial behavioural circadian alterations associated with the disease.
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    Living at the wrong time: effects of unmatching official time in Portugal and western Spain
    (MDPI, 2022-07-28) Casado Ramírez, Elvira; Moreno Casbas, María Teresa; Campos Martínez, Manuel; ModulEN Consortium; Madrid, Juan Antonio; Rol de Lama, María de los Ángeles; Bonmatí Carrión, María de los Ángeles; Fisiología
    Human circadian rhythmicity is subjected to the internal circadian clock, the sun and social clocks (official time, social/work schedules). The discrepancy among these clocks, as occurs when official time does not match its geographical time zone, may produce circadian disruption. Western Spain (GMT+1/+2) and Portugal (GMT0/+1) share similar longitudes (sun time) but have different official times. This provides a unique opportunity to evaluate the effects of official time on circadian rhythmicity and sleep in elderly and retired populations (with no remunerated duties presumed, although other social commitments may be present) at both locations. Although both populations slept enough for their age (7–8 h), circadian robustness (e.g., interdaily stability, relative amplitude) was greater in Portugal, especially during weekdays, while greater desynchronization (both body temperature vs. motor activity and body temperature vs. light exposure) tended to occur in the Spaniards. Once corrected by GMT0, meals took place later in Spain than in Portugal, especially as the day progresses, and a possible interplay between bed/meal timings and internal desynchronization was found. Our results point to the possible deleterious effect on circadian system robustness when official time is misaligned with its geographical time zone.
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    Phase response curve to Light under ambulatory conditions: a pilot study for potential application to caylight saving time transitions
    (MDPI, 2022-10-28) Arguelles Prieto, Raquel; Madrid, Juan Antonio; Rol de Lama, María de los Ángeles; Bonmatí Carrión, María de los Ángeles; Fisiología
    Several studies have investigated the relationship between daylight saving time (DST) and sleep alterations, psychiatric disorders, cardiovascular events and traffic accidents. However, very few have monitored participants while maintaining their usual lifestyle before and after DST. Considering that DST transitions modify human behavior and, therefore, people’s light exposure patterns, the aim of this study was to investigate the potential effects of DST on circadian variables, considering sleep and, for the first time, the human phase response curve to light. To accomplish this, eight healthy adults (33 ± 11 years old, mean ± SD) were recruited to monitor multivariable circadian markers and light exposure by means of a wearable ambulatory monitoring device: Kronowise®. The following night phase markers were calculated: midpoints of the five consecutive hours of maximum wrist temperature (TM5) and the five consecutive hours of minimum time in movement (TL5), sleep onset and offset, as well as sleep duration and light intensity. TM5 for wrist temperature was set as circadian time 0 h, and the balance between advances and delays considering the phase response curve to light was calculated individually before and after both DST transitions. To assess internal desynchronization, the possible shift in TM5 for wrist temperature and TL5 for time in movement were compared. Our results indicate that the transition to DST seems to force the circadian system to produce a phase advance to adapt to the new time. However, the synchronizing signals provided by natural and personal light exposure are not in line with such an advance, which results in internal desynchronization and the need for longer synchronization times. On the contrary, the transition back to ST, which implies a phase delay, is characterized by a faster adaptation and maintenance of internal synchronization, despite the fact that exposure to natural light would favor a phase advance. Considering the pilot nature of this study, further research is needed with higher sample sizes.