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Sleep analysis measured with actiwatch device. Results are given as mean ± SEM (standard error of mean).
Source publication
Light, especially its blue component, is the main synchronizer of circadian rhythms. We investigated effects of suppressed blue band of the spectrum on melatonin production and sleep efficiency in 18 young volunteers. During control days, participants lived in their home environment, and next five days in a room lit only by daylight with windows eq...
Similar publications
Objective
The purpose of this study was to evaluate the applicability of data obtained from a wearable activity tracker (Fitbit Charge HR) to medical research. This was performed by comparing the wearable activity tracker (Fitbit Charge HR) with actigraphy (Actiwatch 2) for sleep evaluation and circadian rest-activity rhythm measurement.
Methods
S...
The mortality rate has risen due to the increase in number of cardiac patients in recent times due to the lack of unawareness of the symptoms. This work mainly aims to detect the anomalies of the rhythmic conditions of the pulse derived from the electrocardiogram (ECG) pattern based on correlation and the method of mapping. As this device is a prog...
We monitored rest-activity rhythm, using the technique of wrist actigraphy, in 20 rotational shift workers (SWs) who have ample opportunity to sleep while availing night shift. This rhythm was also assessed in 20 day workers (DWs). Data were gathered at one-minute epoch length and were analyzed to determine period (ô), autocorrelation coefficient (...
Citations
... The results of these studies showed that the influence of light history and seasonal changes have an impact on the circadian rhythm of melatonin production [20,27]. Additionally, studies dealing with short-wavelength reduction showed no effect of short-wavelength reduction during the day on melatonin production and circadian system synchronization [28][29][30]. ...
Light is the main entrainment agent of the circadian system and has an important effect on the synchronization of biological rhythms. Technical innovations in buildings with advanced glazing systems or shadings can lead to changes in daylight spectral composition in indoor spaces. Our study aimed to find out the effect of a shortwavelength light-reduced environment on the main hormone melatonin metabolite 6-sulfatoxymelatonin in
urine (u-sMEL) and to test the connection between light exposure from the previous day and u-sMEL. Twenty-two participants spent five consecutive working days in the office under normal daylight conditions (reference) followed by five days in spectrally modified light conditions (experimental). The light environment was modified by the blue light-blocking glazing system, which significantly reduced melanopic illuminance in the experimental week. Three urine samples were collected daily and u-sMEL concentrations were measured by ELISA. Light exposure was monitored at the participant’s eye level with LightWatcher and in the office by a stationary spectrophotometer.
The reduction of short-wavelength light during the day did not change the concentration of u-sMEL. In the reference week, there was a positive correlation between personal photopic illuminance and u-sMEL. Both morning and work illuminance under reference conditions influenced u-sMEL production. The significant impact
of illuminance on u-sMEL was found by evaluation of the mean of all three urine samples. In the experimental week, the correlation between illuminance and u-sMEL was not found. The short wavelength and intensity reduction in interiors led to changes in the response of the human biological system to light.
... The data were analysed manually, with correction of sleep start and sleep end according to participants sleep diary or marker. This approach had been used in our previous studies [18,19]. ...
The sleep/wake rhythm is one of the most important biological rhythms. Quality and duration of sleep change during lifetime. The aim of our study was to determine differences in sleep efficiency, movement, and fragmentation during sleep period between genders and according to age. Sleep period was monitored by wrist actigraphy under home-based conditions. Seventy-four healthy participants—47 women and 27 men participated in the study. The participants were divided by age into groups younger than 40 years and 40 years and older. Women showed lower sleep fragmentation and mobility during sleep compared to men. Younger women showed a higher actual sleep and sleep efficiency compared to older women and younger men. Younger men compared to older men had a significantly lower actual sleep, lower sleep efficiency and significantly more sleep and wake bouts. Our results confirmed differences in sleep parameters between genders and according to age. The best sleep quality was detected in young women, but gender differences were not apparent in elderly participants, suggesting the impact of sex hormones on sleep.
... In non-laboratory settings, sensor quality and resolution have hampered some of these efforts Markvart et al. 2015;Price et al. 2017). It is important to note that despite these difficulties, individual photic exposure patterns in real life have often been associated with the dim light melatonin onset as well as sleep structure, quality, duration and timing, suggesting ecological validity of the sensor data collected in some field studies (e.g., de la Iglesia et al. 2015;Dijk et al. 1987;Stebelová et al. 2014;Stothard et al. 2017;Wams et al. 2017;Woelders et al. 2017;Wright et al. 2013). ...
Architectural lighting has potent biological effects but applied lighting practices that capitalize on this potential have been limited. In this review, we endeavor to consolidate and synthesize key references that will be useful for lighting professionals, with the goal of supporting knowledge translation into pragmatic lighting strategies. Specifically, we explain relevant terminology, outline basic concepts, identify key references, provide a balanced overview of the current state of knowledge, and highlight important remaining questions. We summarize the physiological effects of light on human health and well-being, including a description of the processes underlying the photic regulation of circadian, neuroendocrine, and neurobehavioral functions. We review seminal work elucidating the elements mediating the potency of light for these physiological responses, with specific attention to factors critical for interpreting those findings. In parallel, we explain and endorse melanopic Equivalent Daylight Illuminance (Ev,melD65) as the preferred measure to quantify the biological potency of light. Ultimately, while future studies are necessary to further facilitate the translation of laboratory knowledge to domestic and workplace settings, the immediate potential for applied lighting to better support human health is clear. Aiming for integrative lighting solutions that have biologically high potency light during the day and low potency during the night is perhaps the most immediate improvement to be made in order to better support applications for humans.
... The epochs of data recording were set to 1 min. This approach was previously used and validated in our study [44]. ...
... The concentrations of aMT6s were determined by radioimmunoassay using a commercially available kit (Stockgrand LTD., Guildford, UK). The assay was performed according to the manufacturer's instructions using a method adapted for iodinated aMT6s [44,47]. The samples were measured within nine assays. ...
Artificial light at night can have negative effects on human wellbeing and health. It can disrupt circadian rhythms, interfere with sleep, and participate in the progress of civilisation diseases. The aim of the present study was to explore if dim artificial light during the entire night (ALAN) can affect melatonin production and sleep quality in young volunteers. We performed two experiments in real-life home-based conditions. Young volunteers (n = 33) were exposed to four nights of one lux ALAN or two nights of five lux ALAN. Melatonin production, based on 6-sulphatoxymelatonin/creatinine concentrations in urine, and sleep quality, based on actimetry, were evaluated. Exposure to ALAN one lux during the entire night did not suppress aMT6s/creatinine concentrations but did aggravate sleep quality by increasing sleep fragmentation and one-minute immobility. ALAN up to five lux reduced melatonin biosynthesis significantly and interfered with sleep quality, as evidenced by an increased percentage of one-minute immobility and a tendency of increased fragmentation index. Our results show that people are more sensitive to low illuminance during the entire night, as previously expected. ALAN can interfere with melatonin production and sleep quality in young, healthy individuals, and both processes have different sensitivities to light.
... 3. To shade their eyes with sunglasses (or brimmed hat) at all times during their outdoor travels/movements on each session [41,42]. ...
Workplace architectural lighting conditions that are biologically dim during the day are causing healthy individuals to experience light-induced health and performance-related problems. Dynamic lighting was reported beneficial in supporting individuals’ psychological behavior and physiological responses during work period in Europe. It has yet to be investigated in workplaces with minimal/no natural daylight contribution in tropical Malaysia. Hence, an exploratory experimental study was initiated in an experimental windowless open-plan workplace in Universiti Putra Malaysia, Serdang. The aim was to identify dynamic lighting configurations that were more supportive of a morning boosting effect than the control constant lighting, to support dayshift individuals’ psychophysiological wellbeing indicators during the peak morning work period. The immediate impact of a 2-hour morning exposure to overhead white LED (6500 K) with different horizontal illuminance levels and oscillations (lighting patterns) were investigated on physiological indicator limited to urinary 6-sulfatoxymelatonin, and psychological indicators for alertness, mood, visual comfort, cognitive and visual task performance. Not all of the investigated dynamic lighting configurations were supportive of a morning boost. Only configurations 500increased to750 and 500increased to1000 lx therapeutically supported most of the indicators. Both these configurations suppressed urinary 6-sulfatoxymelatonin, and improved alertness, cognitive performance, positive affect, and visual comfort better than ‘visit 1: 500constant500’ lx (control). The increasing oscillation was observed more beneficial for the morning boost in tropical Malaysia, which is in reverse to that specified in the human rhythmic dynamic lighting protocol developed by researchers from the Netherlands for application during winter. The findings from this study present the feasibility of dynamic architectural lighting acting as an environmental therapeutic solution in supporting the individuals’ psychophysiological wellbeing indicators in windowless open-plan workplace in tropical Malaysia. Further investigations on the two prospective configurations are recommended to determine the better supportive one for the morning boosting effect in Malaysia.
... The relationship between light exposure and sleep duration remains less clear. In an intervention-field study, a reduction in daytime light intensity was linked to a decrease in sleep duration 34 whereas, without intervention, the presence of electrical lighting in addition to normal sunlight led to a decrease in sleep duration 35 . This paradox might be explained by the timing of light. ...
... This likely results in lower light exposure 27,33 , and probably a reduction in exposure to ~460-490 nm photons, which are important for entraining the circadian system 63 . In both our dataset and in previous studies, later sleep timing has been shown to be related later clock phase 54,55 and later preceding light exposure 33,34 . These relationships are most likely due to the influence of light on the entrainment of the circadian clock, which drives process C in sleep regulation, which in turn will shift the timing of sleep 6,7 . ...
Study objectives:
To determine the effect of light exposure on subsequent sleep characteristics under ambulatory field conditions.
Methods:
Twenty healthy participants were fitted with ambulatory PSG and wrist-actigraphs to assess light exposure, rest-activity, sleep quality, timing and architecture. Laboratory salivary dim-light melatonin onset (DLMO) was analyzed to determine endogenous circadian phase.
Results:
Later circadian clock phase was associated with lower intensity (R2=0.34, χ2(1)=7.19, p <0.01), later light exposure (quadratic, controlling for daylength, R2=0.47, χ2(3)=32.38, p <0.0001), and to later sleep timing (R2=0.71, χ2(1)=20.39, p<0.0001). Those with later first exposure to more than 10 lux of light had more awakenings during subsequent sleep (controlled for daylength, R2=0.36, χ2(2)=8.66, p<0.05). Those with later light exposure subsequently had a shorter latency to first REM sleep episode (R2=0.21, χ2(1)=5.77, p<0.05). Those with less light exposure subsequently had a higher percentage of REM sleep (R2=0.43, χ2(2)=13.90, p<0.001) in a clock phase modulated manner. Slow wave sleep accumulation was observed to be larger after preceding exposure to high maximal intensity and early first light exposure (p<0.05).
Conclusions:
The quality and architecture of sleep is associated with preceding light exposure. We propose that light exposure timing and intensity does not only modulate circadian-driven aspects of sleep but also homeostatic sleep pressure. These novel ambulatory PSG findings are the first to highlight the direct relationship between light and subsequent sleep, combining knowledge of homeostatic and circadian regulation of sleep by light. Upon confirmation by interventional studies, this hypothesis could change current understanding of sleep regulation and its relationship to prior light exposure.
... To date, multiple studies have tested acute activating effects of exposure to blue light or white light with a high CCT during daytime. These diurnal studies have, however, rendered effects that are considerably less consistent than the nocturnal studies, as results showed both positive as well as negative effects of exposure to blue or blue-enriched light on alertness, cognitive performance, and arousal (e.g., An et al., 2009;Baek & Min, 2015;Boray, Gifford, & Rosenblood, 1989;Figueiro, Nonaka, & Rea, 2014;Gabel et al., 2013;Iskra-Golec, Wazna, & Smith, 2012;Knez, 1995Knez, , 2001Knez & Enmarker, 1998;Mills, Tomkins, & Schlangen, 2007;Okamoto & Nakagawa, 2015;Okamoto, Rea, & Figueiro, 2014;Rahman et al., 2014;Rautkyl€ a, Puolakka, Tetri, & Halonen, 2010;Revell, Arendt, Fogg, & Skene, 2006;Sahin & Figueiro, 2013;Stebelov a et al., 2015;Vandewalle et al., 2007bVandewalle et al., , 2007aViola, James, Schlangen, & Dijk, 2008). ...
Research in the late evening and at night has shown that acute activating effects of light are particularly sensitive to short-wavelength light. Yet, findings on such effects during daytime are still inconclusive. This study (N = 39) investigated effects of correlated colour temperature (CCT; 2700 K vs. 6000 K, 500 lx on the desk) on individuals' experiences, performance, and physiology during one hour of exposure in the morning versus afternoon. Except for a higher subjective vitality in the 6000 K condition in the morning, results showed no significant activating effects, and even subtle performance-undermining effects in the relatively high CCT condition. Moreover, participants rated both their mood and the light settings as less positive in the 6000 K vs. 2700 K condition. It is therefore questionable whether lighting solutions with commonly experienced intensity levels should provide a higher CCT during daytime office hours.
... It is generally accepted that melatonin biosynthesis can be eff ectively monitored by measurement of the urinary aMT6s, which represents a predominant metabolite of melatonin (Bojkowski et al. 1987b;Graham et al. 1998). Levels of melatonin metabolite in our study are in the line with the concentrations measured in published studies (Karasek 2004;Stebelova et al. 2015). ...
Objective. Melatonin is a hormone predominantly synthesized and secreted during the night by the pineal gland. Artificial light at night, especially its blue part, acutely suppresses the melatonin production. Th e aim of the present study was to find out, whether an intense blue light phototherapy of severe hyperbilirubinemia, may suppress the melatonin production during the night when the eyes will be properly protected by a sleep mask.
Methods. The main melatonin metabolite, 6-sulphatoxymelatonin was measured in urine in a nine-year old boy suffering from the Crigler-Najjar syndrome type I. The boy was treated during the sleep period with an intense blue light (to 1800 lx) 10 h/day, since his birth. During the phototherapy, his eyes were protected with a sleep mask. The concentration of 6-sulphatoxymelatonin was determined in the first morning urine and urine collected afternoon during the six days. The patient was exposed to phototherapy for three nights, two nights without and the last one with the treatment. The control urine samples were obtained from 8 healthy nine-year old boys. The level of 6-sulphatoxymelatonin was measured by radioimmunoassay and the data were normalized to urinary creatinine.
Results. A distinct melatonin production rhythm was found and 6-sulphatoxymelatonin concentration in urine of the patient was comparable with the values obtained by the control group. No differences in 6-sulphatoxymelatonin levels were found between the nights with and without the phototherapy applied.
Conclusions. We conclude that the whole night treatment of hyperbilirubinemia with intense blue light has negligible side effect on the rhythmic melatonin production, when the eyes are sufficiently protected by the sleep mask.
One of the most striking changes in the regulation of sleep–wake behaviour during adolescence is circadian phase delay. Light exposure synchronises circadian rhythms, impacting sleep regulation, however, the influence of real‐life light exposure on sleep variations remains less clear. We aimed to describe the sleep and light exposure patterns of high school students with comparable schedules and socio‐economic backgrounds, and to evaluate whether there was any association between them, considering chronotype. We analysed five school days and two free days of actigraphy records, from 35 adolescents (24 female, mean age: 16.23 ± 0.60). The sample was described using the Sleep Regularity Index (SRI), chronotype (actigraphy MSFsc), and self‐reported diurnal preference (Morning/Evening Scale). Regression models were constructed to assess the impact of light exposure (daytime and nighttime) on subsequent sleep episodes; and to confirm whether the associations could be an indirect consequence of chronotype. Despite following similar routines, the SRI varied considerably (48.25 to 88.28). There was compatibility between the actigraphy proxy for chronotype and the self‐reported diurnal preference, extracted using the circadian rhythm scale for adolescents. Less light exposure during the day was associated with later sleep onset and shorter sleep duration. An increase of 100 lux in average daytime light exposure advance of 8.08 minutes in sleep onset and 7.16 min in sleep offset. When the regressions were controlled for chronotype, these associations persisted. These findings facilitate discussions regarding the behavioural aspect of the impact of real‐life light exposure on sleep and its potential as a target for interventions aiming to enhance adolescents’ sleep quality.
