Can’t fall — or stay — asleep? Or feel sluggish during working hours? Adjusting your lighting may be the solution. 

Natural and artificial light both significantly impact our circadian rhythm, which is the “biological clock” that drives our sleep-wake cycle. When the sun was our primary light source, circadian rhythms were rarely disturbed — we slept when the sun set and woke up when the sun rose. Now, though, we’re heavily reliant on artificial lighting, impacting our body’s natural ability to regulate sleep and wakefulness. 

Understanding circadian rhythm 
Circadian rhythm is triggered by changes in environmental lighting. Human circadian rhythms work on a 24-hour schedule and regulate how we conserve and use energy.

So how does this regulation work? Each of our master body clocks include a cluster of approximately 20,000 nerve cells found in the brain’s hypothalamus and is triggered by the light our eyes take in. These signals allow the brain to automatically sense the time of day, releasing appropriate hormones to encourage wakefulness or rest. This cycle also moderates our metabolism and helps us to maintain a steady body temperature.

How do circadian rhythms affect sleep and wakefulness?
Our circadian rhythm also helps control the release of melatonin, serotonin and cortisol. Melatonin naturally promotes sleepiness, while cortisol increases alertness and serotonin boosts our mood and energy level. Our bodies sense when to release these hormones based on the color temperature of our immediate surrounding light.

Light on the brighter and bluer side of the spectrum – similar to sunlight in the morning and midday — encourages production of cortisol and serotonin, while light on the softer and yellower end of the spectrum – similar to evening light — encourages melatonin production.

Translation: it’s instinctively harder to stay awake under dimmed incandescent lamps or candlelight. And it’s equally harder to fall asleep under strong fluorescent light. That’s because an incandescent lamp or candlelight imitates the soft yellow light of early evening, while fluorescent light imitates the brighter and bluer light of midday.

It’s important to consider these implications since lack of sleep or disrupted sleep can significantly impact our health and well-being. A 2016 report by a team of U.K.-based scientists published in Endocrine Reviews explains that sleep disruption can lead to impaired metabolic and hormonal function, resulting in obesity and a range of cardiometabolic diseases, including diabetes, hypertension, and heart disease.

Circadian Rhythms & Artificial Light
Until recently, it was virtually impossible to support the natural circadian cycle with artificial light since a bulb’s color temperature is fixed. For example, traditional incandescent bulbs emit a warm color temperature of 2,700K, while commercial fluorescent lights emit a cooler color temperature between 5,000K and 6.500K.

With the advent of LED and smart lighting technology, though, it’s now possible to adjust color temperature with total precision — and to schedule changes in light color temperature over the course of a day. In multi-use areas like kitchens or bedrooms that double as home offices, these smart lights enable people to optimize light color relative to the activity and the time of day.

The Viro smart pendant light, for example, helps maintain healthy circadian rhythms and promote better sleep using the “Rhythms” automation on the Viro app. It’s also easy to shift the brightness and color temperature of your Viro smart pendant from “daytime” to “nighttime” modes, boosting productivity and alertness during the day, encouraging restfulness in the evening, and supporting your overall health.