New research and innovative lighting products are highlighting the importance of mimicking natural sunlight indoors to support our circadian rhythm and overall wellbeing.
Our circadian rhythm, or internal body clock, governs more than just sleep; it regulates hormone release, temperature, digestion, gut bacteria, and immune response. The shift to energy-efficient LED lighting in recent decades may be disrupting this balance. A 2023 House of Lords Science and Technology Committee report called artificial lighting a “hidden pollutant,” noting that invisible LED “flicker” can overstimulate the brain, and that LEDs are primarily blue light, which affects circadian rhythm.
The Case for Sunlight-Mimicking Bulbs
Russell Foster, professor of circadian neuroscience at Oxford, warns against invading the night with artificial light. He notes that in the 1800s, most people lived by natural light, but now we have become “cave dwellers again.” He advocates for bulbs that are as close to sunlight as possible.
Lighting brand Ray is pioneering “human-centric” lighting in the UK, with systems that eliminate flicker and use horticultural-standard LED chips to minimize blue light, making them the closest bulbs to sunlight on the market. Co-founder Simon McCune explains, “If the plants think it’s the Sun, it must be good for us too.”
Practical Steps and Expert Insights
Both McCune and Foster agree that getting outside is key, especially for “dawn and dusk detection” which syncs our biological clock. Using a lux meter app, you can see the vast difference: outdoor light is over 10,000 lux even in shade, while a well-lit room is about 1,000 lux.
Interior experts also emphasize biological lighting. Alice B Davies, co-founder of Salon, says, “The importance of lighting goes far beyond the visual — it’s a biological and physiological imperative.” She works with lighting designer Simone Adler to prioritize biological lighting in spaces.
Ray’s bulbs have a colour resolution index (CRI) of 98, compared to halogen’s 100 and standard LEDs’ 80, meaning colors appear as they would under sunlight. Foster notes that scientists are only beginning to understand light’s effects, and nature still does it best.
