Sleep is fundamental to our health, performance, and wellbeing — yet it is increasingly disrupted by our everyday’s actions and the way we design and light our buildings. This CIBSE-approved CPD course explores the science of sleep, our internal body clock, and how integrative lighting design can actively support healthier sleep–wake rhythms. Photo by Gregory Pappas on unsplash Understanding sleep: more than just “switching off” A clear overview of what sleep actually is, bre

Sleep doesn’t start when your head hits the pillow, it begins hours earlier with the signals you send your brain. One of the most important signals is light. To support deep, restful sleep, it’s recommended to keep light levels below 10 lux starting three hours before bedtime. Photo by Giorgio Trovato on Unsplash   How Light Affects Your Sleep Your brain uses light to decide whether it’s time to be awake or asleep. Bright light in the evening, especially artificial lighting a

Last week, Jan Denneman had the opportunity to speak at Light + Building in Frankfurt as Chair of the Good Light Group. What continues to strike him is this: we spend around 90% of our time indoors, yet the light around us is fundamentally misaligned with our biology. The impact is not subtle. It shows up in poor sleep, low energy, reduced wellbeing, and long-term health risks. And still, we treat this as normal. The reality is simple. During the day, most indoor environments

Spending time outdoors is ideal, but many of us still spend large portions of the day inside. When natural daylight is limited, optimizing your indoor light environment becomes essential for maintaining energy, focus, and a healthy daily rhythm. These two simple steps can make a big difference.      Photo by Surface on Unsplash     Step 2: Stay within one meter of a window When you’re indoors, your proximity to natural light matters more than you might think. Light intensity

In our busy, screen-filled lives, it’s easy to spend most of the day indoors. But making time to step outside, particularly in the morning, can have a huge impact on your overall health and well-being. In fact, scientists recommend spending at least 2 hours outside during the day, with a good portion of that time in the morning if possible. Photo by cal gao  on Unsplash   The power of morning light Morning sunlight plays a vital role in setting your body’s brain clock, also k

A blog by Ivo Habets “Natural daylight during office hours improves glucose control and whole-body substrate metabolism” The circadian timing system regulates many processes in the human body. While it is best known for controlling our sleep–wake cycle, metabolism also follows a strong daily rhythm. This includes processes such as glucose regulation, insulin sensitivity, and substrate use, which vary across the day in a coordinated manner. The main entrainment signal for the

A blog post by Dr. Aida Farshadi For millions of years, humans lived under the full spectrum of sunlight. Our physiology evolved not just with visible light, but also with near-infrared light (NIR), an invisible wavelength that makes up nearly half of the sun's energy reaching Earth. Photo by Todd Rhines  on Unsplash What is near-infrared light and why we're missing it? Near-infrared sits just beyond the red end of the visible spectrum, in the 700–1100 nm wavelength range. Un

Summary of Ulysse Dormoy’s article “What Is Light?” “It occurred to me that since I started posting articles and thoughts about light, I haven’t yet raised the question - ‘ What is Light? ’ – actually, in 30+ years in the lighting industry it's not a question I've challenged myself with.” – Ulysse Dormoy Light exists in a state of duality. It behaves both as a wave and as a particle, a phenomenon known as wave–particle duality. Like the classic “chicken or egg” question, it c

It’s Blue Monday, often described as the “most depressing day of the year”. Three weeks in the new year, mostly in cloudy, rainy of snowy weather has brought the mood down of many. Photo by Pars Sahin  on Unsplash   Here are some tips and tricks to help you get through this day. Boost your mood naturally Get a lot of daylight: We recommend spending up to two hours outside, especially in the morning. But every short walk outside does already help. Move your body: If you’re goi

A blog by Timo Partonen From November to January, if your exposure to daylight is of 1 hour or longer per day, it is likely that you will not have depressive symptoms during that period of the year. Compared to the conditions where your exposure of less than 1 hour per day, the odds of having depressive symptoms will be 0.72 on average, yielding the confidence interval from 0.60 to 0.82. If you have children younger than 12 years of age at home, it is even more likely that yo

Every living organism on earth follows internal 24-hour cycles known as circadian rhythms. From a flower opening at dawn to a surge of human alertness in the mid-morning, these rhythms are deeply embedded in our biology. They regulate countless processes, from gene expression and metabolism to behaviour and sleep. In mammals, the central pacemaker of this system is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN synchronises peripheral clocks that ex

In this episode of the Happier with Light podcast, Lard talks with Jan Denneman, Chairman of the Good Light Group. Jan shares why the organisation was founded and how everything it does is based on science. More than thirty scientific advisors and experts in fields such as chronobiology, neurophysiology, sleep, psychiatry and light, support the group in shaping its message and grounding every insight in solid research. Jan reminds us of something that is often overlooked: mos

Light affects how we sleep, feel, and perform – yet public awareness of its impact remains limited. The Light for Public Health  initiative aims to make evidence-based knowledge on light and health both accessible and actionable, thus turning scientific insight into public benefit. “Light isn’t just for vision – it is a key signal for human biology,” says Manuel Spitschan, research group leader at the Max Planck Institute for Biological Cybernetics and professor at the Techni

It’s almost the time of the year again, the day in autumn when the clocks turn back to natural time. Every year, millions of people groan, lose sleep, and wonder, why are we still changing our clocks to daylight saving time in the summer? The seasonal clock change is one of those traditions that perhaps made sense once upon a time but no longer serves us. In fact, modern science is increasingly clear: switching the clocks twice a year disrupts our health, our productivity, an

Good light changes lives. A peer-reviewed study “ Biodynamic lighting effects on the sleep pattern of people with dementia ” reports that good light, either daylight or light that compensates for a lack of daylight, has a substantially positive influence on people with dementia. The results are both humane and practical: better sleep at night, greater alertness by day, and less restlessness overall. What the research found Under good light conditions, residents experienced: L

In this episode we’ll be focusing on how to measure light. To guide us through this topic, we’ve invited Hedy Lee from UPRtek, a...

Lighting is often treated like background scenery. Yet it quietly shapes energy use, cognitive performance, sleep quality, and even the...

What if lighting were no longer seen merely as an energy issue, but as a key to health, productivity, and well-being? Photo by Copernico...

In this episode we’re talking about sleep and light: how daylight sets your body clock, helps you drift off at night, and also why that...

Just checking that one last thing or just one more scroll and suddenly it’s 00.00, your thumb hurts, your eyeballs are twitching, you...