Good indoor lighting is essential for enhancing healthy bodily rhythms, sleep quality, alertness, mood and workplace productivity. Current practices and recommendations for indoor lighting, however, prioritize vision over health, leading to disruptions in our biological clock and alertness. Limited exposure to natural daylight also contributes to this problem. Scientific recommendations for people following regular daytime schedules call for higher light levels during the day and lower levels in the evening and night.
Adopting these good lighting recommendations in norms and regulations will lead to improved indoor lighting and overall well-being for individuals as well as having a significant socioeconomic impact.

THE DARK SIDE OF INDOOR LIGHTING: HOW IT’S DISTURBING

Our Biological Clock In modern times people spend up to 90% of their time indoors, resulting in limited exposure to natural daylight. Unfortunately, indoor lighting practices mainly focus on visual and aesthetic experiences and low energy consumption with little consideration for the health aspects of light. As a result, indoor light intensity is too low during the day and too high in the evening and at night. This interferes with the natural regulation of the biological clock causing disruptions in many areas like our sleep-wake cycle and alertness.
Because people spend so much time indoors, indoor lighting should promote the natural regulation of the biological clock and support our sleep-wake cycle, alertness and mood, in addition to providing adequate illumination for visual tasks and ambiance. The field of knowledge on the health effects of light is mainly based on chronobiology. Chronobiologists investigate 24h rhythms, the biological clock and how adaptations of the clock to the environmental light-dark cycle are instrumental for health and well-being. This field received the Nobel Prize in Physiology or Medicine in 2017. Now is the time to implement the insights into daily practice.
Recent scientific recommendations propose that indoor light levels, necessary for proper adjustment of the biological clock and supporting alertness, should be two to five times higher during the day and much lower in the evening than is currently the case in working and home environments.
The technicalities of these recommendations are available in international standards, but they are not yet included in norms or regulations.
Good light indoors provides the right light intensities with the right spectrum, at the right time of day. Implementing regulations for good indoor lighting can support overall health and well-being.

SHEDDING LIGHT ON THE BETTER SLEEP

Sleep is crucial for overall health and wellbeing, but up to 20% of the population may experience insufficient or disrupted sleep, leading to daytime sleepiness and other negative effects.
Good light exposure plays a vital role in regulating the body’s biological clock and can improve sleep quality for example by reducing the time needed to fall asleep, increasing deep restorative sleep and increasing the likelihood of waking up feeling more rested in the morning. The improved sleep quality may, in turn, lead to better cognitive function, memory, learning, athletic performance, physical coordination and a lower risk of accidents, injuries, and occupational errors.
On the other hand, sleep deprivation has been linked to an increased risk of chronic conditions such as obesity, diabetes, and cardiovascular disease.

LIGHT UP THE DAY TO BOOST ALERTNESS AND MOOD

Although a clear dose response curve for immediate effects of daytime light on alertness is not yet established, it is clear that sitting in relative darkness makes you sleepy. Increasing light intensity in an attractive way can have an immediate alerting effect on the human body, leading to increased alertness, attention, and cognitive performance. It can help reduce fatigue, improve mood, and boost mental acuity, making it an invaluable tool in workplaces where focus and productivity
are essential.
Studies have shown that good light exposure can also enhance well-being, alleviate symptoms of depression and anxiety and increase positive emotions. In fact, bright light therapy is a highly effective treatment for seasonal affective disorder (SAD) and related depressive symptoms.
If applied early in the development of symptoms, studies have shown that it may prevent the full-blown development of a serious depressive episode.

BRIGHT IDEA FOR INDIVIDUALS AND SOCIETY

Investing in good indoor lighting can improve individual health and well-being and has the potential to lower healthcare costs and boost workplace productivity.
Good lighting can reduce the cost of sick leave (absenteeism) and presenteeism, potentially amounting to up to $410 billion per year [18], or $550 per capita for the five major OECD countries.
While the long-term economic impact of good light on health and well-being is yet to be determined, investing in good indoor lighting can definitely benefit individuals, companies, and governments.

Authors
Jan W. DENNEMAN: Light Expert, Chairman Board Good Light Group
Marina C. GIMÉNEZ: University of Groningen, The Netherlands, Chrono@Work
Bruno M.J. SMETS: Light Expert, Board Member Good Light Group
Roger SEXTON: Light Expert, Board Member Good Light Group, Stoane Lighting
Marijke C.M. GORDIJN: Board Member Good Light Group, University of Groningen, The Netherlands, SLTBR, Chrono@Work

Source – magazine Led Professional (issue may/june 2023)