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Tone Henriksen is Science Advisor of the Good Light Group, and co-author of the scientific article on the effect of blue-blocking glasses on melatonin onset during pregnancy. All life is adapted to the natural light-dark cycle produced by the 24-hour rotation of the earth. Even before we are born, we get a time-cue from the outer environment from our mother’s night hormone melatonin. Melatonin passes freely over the placenta and seems to be important for a healthy pregnancy in several ways. The hormone of darkness plays an important role for the placenta – the organ securing oxygen and nutrition to the fetus. Melatonin is a strong free radical scavenger and has neuroprotective function for the growing fetus. Nevertheless, melatonin protection is not part of the general advice to pregnant women – yet. Recent evidence suggests a simple way of protecting pregnant women and fetus from melatonin shortage, without the need to stay in real darkness. As it turns out, all light is not equal when it comes to suppressing the darkness hormone melatonin. To the brain-, light containing high portions of blue frequencies is interpreted as daylight. Natural morning and mid-day sunlight have a high portion of blue. In 2014, Shuji Nakamura won the Nobel Prize in Physics for inventing blue emitting LED diodes-, which was necessary for making white and bright indoor lighting, similar to sunlight. However, in the natural condition, the sun sets in the evening. Image a camping bon-fire, far away from electric lighting. No blue light there, and melatonin production in the brain starts fine-tuned and synchronized to the internal circadian rhythm and natural environment. This is a nice scenario but, except during holidays, hardly a practical advice to pregnant women. Could blue-blocking (BB) glasses work as well? Randi Liset and co-authors in Bergen, Norway, conducted the first trial testing the melatonin protective effects of amber glasses (99% blue-blocking) as compared to grey control glasses (approximately 50% blue-blocking) for healthy pregnant women in the third trimester (N=60) A randomized controlled trial on the effects of blue-blocking glasses compared to partial blue-blockers on sleep outcomes in the third trimester of pregnancy - PMC (nih.gov) Both groups wore the glasses for three hours prior to their preferred bedtime. After two weeks, the BB-glasses group had 43 minutes earlier melatonin onset and the control group 11 minutes earlier melatonin onset than at baseline. The adjusted difference of 28 minutes was highly significant. The superiority of the near 100% blue-blocking over the partially blue-blocking control condition was clear. This shows the need for blocking as much blue light as possible in the evening for optimal protection of the rise of your melatonin. These glasses seem an easy way to effectively lower melanopic lux levels in the evening. Other studies have shown that more daylight during the daytime increases the capacity of producing melatonin the following night. Follow-up studies combining daytime light exposure and evening blue-blocking are wanted. For now, this novel study by Liset et al. provided the first evidence that BB-glasses worn in the evening for three hours before bedtime can serve as a simple, low-cost and safe means of non-pharmacological strengthening of circadian health for mother and fetus.

Our board member Marijke Gordijn was asked to give a presentation about nightlife from different perspectives for the Nature Bits program. A nature education group which organized a camping trip on Texel, an island of the Netherlands, to watch the milky way and learn about the effects of light and darkness on nightlife and humans. The right light at the right time In the vlog you see what Marijke means with the right light at the right time, or how we call it ‘Good Light’. Want to know more about good light? Read our other news blogs, for example: Why do we sleep so late Nature bit is a program for people between 18 and 30 that want to be actively involved in a greener and more sustainable future. How? To learn as much as possible about nature and share this knowledge with other people. Watch the vlog here Nature Bits

All lectures are now online, so if you missed it, you can now enjoy listening to the three different topics and learn more about light. In the free webinar deLIGHTed talks several lighting experts talk about various aspects of what light does to our health. In cooperation with the Daylight Academy, Society of Light Treatment and Biological Rhythms, International Association of Lighting Designers, Luger Research we organize the deLIGHTed talks webinars. Four light professionals were invited to talk about Healthy Lighting Recommendations, Bright days, Dark nights and to lead the panel discussion. You can now watch the lectures online here: Dr. Luc Schlangen - Introduction on Healthy Lighting Recommendations He will give a brief introduction on a recently published set of recommendations for bright days, dim nights and indoor light exposures to best support human physiology, sleep and wakefulness in day-active people. Watch the lecture Dr. Christine Blume - Bright Days Beyond sleep, daylight has repeatedly been shown to have beneficial effects on mood. In her talk, Dr. Blume will outline the scientific basis of her recommendation, that the foundation for good sleep is laid during the day - with adequate exposure to daylight. Watch the lecture Koosje Lamers, MSc. - Dark Nights During this presentation, we will explore the importance of dark nights, and the implications of light pollution for our own wellbeing, cultural history, and our natural environment. We will touch on solutions and discuss how initiatives like the Darkness of the Wadden project can combine fighting light pollution with sustainable development. Watch the lecture Curious about the panel discussion? Carla Wilkins together with the other experts answer a lot of questions from the attendees. Watch the panel discussion here More information about the experts or lectures here

Oliver Stefani, Participant of the Good Light Group, analysed and summarized a new scientific article on predicting melatonin suppression. Variations in light conditions, both in terms of intensity and spectrum, are an important determinant of non-visual effects of light on people. Light is the principal synchronizer (i.e. Zeitgeber) of human circadian rhythms. Light exposure during the biological night can lead to sleep and circadian rhythms disturbances. In particular in the evening and at night, light with a high proportion of short wavelengths in the blue spectral range suppresses the secretion of the hormone melatonin. This hormone is naturally produced during the biological night and supports darkness related behaviour. The onset of melatonin production (in dim light) is a marker of the circadian rhythm in humans. To support good health and sleep, the evening increase in the body's own hormone melatonin should be attenuated as little as possible. But how do we define little, and how long can this exposure last? What plays a bigger role: timing, duration, brightness or spectral composition of the light? The latest publication in J Pineal Research provides a first set of insights for answering this riddle. The authors used machine learning to analyze light-induced melatonin suppression data from 29 peer-reviewed publications. The suppression of melatonin was primarily dominated by the spectral composition of the light exposure which defines the quantity melanopic EDI. The CIE uses this quantity in its recommendations on proper light at the proper time for Integrative and Human Centric Lighting applications. An exact dose, however, was not yet provided in the CIE recommendations. The authors used a logistic model to predict the melatonin suppression response based on various characteristics of the light exposure (duration, spectral composition, pupil dilator usage etc.). The model predicts that for light exposure durations of 0.5, 1, 2, 3 and 4 hours, nocturnal melatonin secretion is reduced by 50% when the light exposure has a melanopic EDI of 600, 350, 120, 43 and 15 lx, respectively. This confirms and extends insights on the metric melanopic EDI being an important predictor of biological effects of light within integrative (human-centric) lighting applications. As a metaphor, one could compare the melanopic EDI of our light environment to the caffeine content of a drink: a small espresso or a big cup of normal coffee provide the same dose of caffeine. The publication and a small toolbox (see Supporting Information) can help lighting practitioners to better estimate the effect of light exposure on melatonin suppression. The publication, the toolbox and a video about it can be found in the Journal of Pineal Research here: https://onlinelibrary.wiley.com/doi/full/10.1111/jpi.12786

Independent research has shown systemic health benefits of the Seaborough technology SunLED This means: near-infrared light that shines on your face and neck, results in whole-body effects including lowered resting heart rate, better mood, and boosted immune system. The principal investigator Marijke Gordijn from Chrono@Work B.V. / University of Groningen will tell you everything about the study in our webinar on June 7, 3 pm (CEST). Join the webinar, to learn more about: - How the study was organized - What the results are - How strong the evidence is Subscribe for free at Seaborough

Since the first quarter of 2022, the Good Light Group introduced the concept of Science Advisors. Next to the existing Participants and Partners they are supporting the Good Light Group. Their role is to ensure that the information, claims and guides are based on scientific arguments. The Good Light Group has already 20 Science Advisors in various fields of expertise such as chronobiology, light and health, sleep, neuroscience, psychiatry, and medicine. The multidisciplinary input will support the Good Light Group in bringing a complete story on the importance of good light and the impact of light on people. The outreach to individual scientists to join as Science Advisors proved to be a very practical way to involve many scientists in the work of the Good Light Group. For the latest update on the Science Advisors, see the dedicated webpage: https://www.goodlightgroup.org/science-advisors. Scientists who would like to join as Science Advisor can contact info@goodlightgroup.org for more information.

A couple of our science advisors wrote some blogs about Good Light. In this blog Daan Van Der Veen, Science Advisor of the Good Light Group, watched and summarized the new animation ‘Why do we sleep so late’. In a new animation by researchers at the University of Surrey, UK, it is explained how artificial light exposure at night is driving us to delay our bedtime and leaves us tired and reluctant to start the day when the alarm clock wakes us the next morning. Humans – and many other species on our planet – have evolved internal biological clocks that drive daily rhythms in our sleep and activity patterns. But in contrast to our wrist watches or alarm clocks these biological clocks do not run to exactly 24 hours - depending on the species, biological clocks express a period that is slightly shorter or longer than 24 hours. To ensure that these biological clocks stay synchronised with the 24-hour day on earth, a mechanism evolved by which daylight adjust the timing of these internal clocks each day. If morning light exposure falls earlier than expected, humans move the arm of their internal clock forward to catch up; if evening light falls later than expected, the arm of the clock is moved back to delay starting the restful evening and subsequent sleep. In the modern world we are exposed to electrical light late in the evening, and as a result we are delaying our biological clocks and holding back on a timely start of our sleep. If late sleep then also leads to late waking (but this is often only in weekends for many people in e.g. daytime employment or school-going children), we miss out on the important morning light that synchronises our clocks and rhythms to drive active wakefulness. The solution, Professors Dijk and Skeldon indicate, is to actively seek bright morning light exposure and avoid bright light in the evening. This will keep our biological clocks synchronised and promote timely sleep and waking. This animation nicely shows why good timing of daily light exposure is so important for sleep, and by extension also suggests that regularity of this light exposure is key to good synchronisation of biological clocks. It’s not just about the timing - the characteristics of the light will have an impact on both the response of the biological clock, as well as the direct effects of light on sleepiness. As the authors say: light is both the problem and the solution, and tailoring timing and quality of artificial light exposure in our urbanised, 24-hour society will be hugely important to driving timing of good quality sleep, and many other daily behaviours that contribute to health and wellbeing. Watch the video here

You can now join the free 3rd edition of the Good Light - Good Life webinar and learn why Bright Days and Dark Nights have such an important influence on your health and sleep. After the lectures you can join the panel discussion to discuss all aspects and your experiences with Good Light during the day and less light during the night. We organize the deLIGHTed talks webinars together with the Society for Light Treatment and Biological Rhythms (SLTBR), the Daylight Academy (DLA), the International Association of Lighting Designers (IALD), and Luger Research (LR). Register and more info

Tuesday the 26th of April, we organized the 10th Good Light Group meeting. In this meeting there were three participants that gave a short presentation about either new research, their company and new innovations. In this meeting Anne Berends talked about her company Seaborough and meaningful light innovations for a better and healthier world. The second presentation was given by Daniel Tschofen of the company Wirklicht about their new innovations and the third was given by Inge Declercq about a citizen science project on light exposure, physical activity and sleep throughout the seasons. #1 Anne Berends - Seaborough Beyond the visible: SunLED brings inside the healthy near-infrared part of sunlight. Seaborough develops new technologies for the lighting industry, focusing on sustainability, light quality and health. SunLED is our newest technology that integrates near-infrared radiation in lighting products to improve the indoor environment. The positive effects on health and well-being of their technology are now proven in a clinical study. #2 Daniel Tschofen – Wirklicht What are the luminaires of the future? Natural materials and innovative technology will make a real difference. A brief overview of how sustainability and good light can be translated into luminaires. #3 Inge Declercq – neurologist, sleep expert, SleepWell & StressLess, UZAntwerpen Brainstorm on idea for citizen science project & looking for partners. The project is Belgian (as for now) and aims at gathering a large amount of data on sleep-wake habits of Belgians.

We've added a new Good Light project! A nursing home for people with dementia started to use biodynamic lighting. Before they started using the Good Light, there was a lot of behavioural disturbances and tumult in the nursing home which expressed itself especially at night when some residents started banging the doors, dragging furniture or even physically fighting each other. Photo by Dominik Lange on Unsplash The lamps help to regulate the residents' biological clocks, improving their day-night rhythm. But this does not automatically eliminate all sleeping problems, Engeline says: "If the behavioural disturbances are caused by an irregular rhythm, the lamps will resolve this. But a lamp does not replace an employee. The employee simply has more time left to help people. To help the people who are awake or restless for other reasons, for example because they are in pain or suffer from sleep anxiety." Read more about the project here Visit Sparckel to learn more about the lights

In a previous blog we wrote about a preprint publication of 18 scientist that agreed on recommendations for daytime light and evening light in indoor environments. These recommendations are meant for adults for a better sleep during the night and more energy during the day. The publication is now finalized and published. This news post is a brief summary by one of the authors dr. Luc Schlangen. Photo by Copernico on Unsplash The human indoor light environment strongly differs from the natural light-dark cycle outdoors, both in spectrum and amount of light exposure. The ubiquitous availability of electric light enables us to spend large parts of our day indoors, in conditions with limited, or sometimes even without, any natural daylight. Across daytime we therefore expose ourselves to relatively dim light conditions, while during the evening and at nighttime the abundant use of electric light deprives us of natural darkness. Consequently, in our 24/7 society, we experience dimmer days, brighter nights and a much smaller day-night contrast as compared to natural light-dark cycle outdoors. This has negative consequences for our daily mood and functioning, as well as for our sleep, health, and well-being. Our 24-hour exposure to light and darkness has important influences on our physiology and behaviour. It regulates our circadian rhythms and affects our mood, daytime functioning and nighttime sleep. These effects are mediated by a (melanopsin-based) photoreceptor that is maximally sensitive to the short wavelength portion of the visible spectrum around 480 nm, unlike vision which is dominated by the traditional rod and cone photoreceptors. The spectral sensitivity of the long and medium wavelength sensitive cones defines the units lux and lumen that are commonly used to characterize the brightness of our light environment as experienced by an average human observer. However, for circadian and other non-visual effects of light on physiology and behaviour the traditional units lux and lumen are less appropriate. Recently an international expert workshop on circadian and neurophysiological photometry, developed a set of recommendations to best support human physiology, sleep and wakefulness in day-active people within indoor settings. The workshop specified bright days and dim nights, not with respect to vision, but for the non-visual functions of light which are typically driven by the melanopsin-based photoreceptor. For this photoreceptor, the brightness of a light condition can be specified in terms of a recently-developed and standardized metric, melanopic equivalent daylight illuminance (melanopic EDI). The recommendations are published in PLOS Biology and specify what daytime, evening and nighttime light exposures are best to support human health and wellbeing. The recommendations provide highly needed further guidance towards truly integrative lighting solutions, but are not meant to supersede existing guidelines and regulations relating to for instance visual function, comfort and energy consumption. The expert consensus-based recommendations from the workshop are: Throughout the daytime, the recommended minimum melanopic EDI is 250 lux at the eye measured in the vertical plane at approximately 1.2 m height (i.e., vertical illuminance at eye level when seated). If available, daylight should be used in the first instance to meet these levels. During the evening, starting at least three hours before bedtime, the recommended maximum melanopic EDI is 10 lux measured at the eye in the vertical plane approximately 1.2 m height. The sleep environment should be as dark as possible. The recommended maximum ambient melanopic EDI is 1 lux measured at the eye. In case certain activities during the night-time require vision, the recommended maximum melanopic EDI is 10 lux measured at the eye in the vertical plane. dr. Luc Schlangen, Eindhoven University of Technology, Eindhoven, The Netherlands

After almost two years of working from home, most of you have created a Home Office in your house. But have you also added Good Light, in line with the Good Light Guide? Or are you still using the ceiling lamp that was already in the room before you started to use it as your Home Office? Good Lighting for your Home Office can be realized in multiple ways and is really easy to install. Just read the Project example of the WiZ Home Office by Signify and be inspired to upgrade your own Home Office. It is part of the mission of the Good Light Group to have 100,000 practitioners working in Good Light by 2025. So, make sure you practice as you preach. For Participants, Partners, Science Advisors and Friends of the Good Light Group in the Benelux, it is now possible to order your WiZ high lumen bulbs & WiZ Remote control to create your own Good Light Home Office at Light Gallery with a special ambassador discount code: GoodLightGroup220120Rs#07ja