When was the last time you gave much thought to the harsh, interior lights above your desk during the day? We certainly notice when a rough night’s sleep makes us groggy. Is it possible that lighting plays a role in how we feel, just like sleep does?

We humans have a biological clock that is synchronized with daylight. It’s called a circadian rhythm. It helps us stay in sync with the environment as the seasons change, and regulates many of our normal health functions. It’s the reason we feel off during daylight savings time, or when we travel abroad and hop multiple time zones.


The National Human Activity Pattern Survey (NHAPS) found that people spend on average 87% of their lives indoors – often without access to natural daylight. Artificial light makes it tough to tune into the natural rhythms of the day, which significantly impacts our health and productivity.

Real estate leaders who value wellness should take notice. The fundamental principles of lighting and its effects on human circadian rhythm should become an industry standard.

Thankfully, the link between lighting and human health is already well-studied and solutions are available on the market. One example is circadian lamps. These LED lamps are designed to promote alertness, performance, and well-being by using color, lighting level, and timing to align natural human rhythms (our internal ‘clock’) with the world around us. In other words, the right amount of the right light at the right time.

Cycled Lighting Promotes Wellness

How do they work? The circadian lights are programmed to change color temperature and light level, replicating the natural lighting found outdoors. For example, you’ve likely heard that looking at our screens (computers, tablets, phones) late at night does not help one sleep. There’s a good reason for that. These devices often produce a blue light. Yet, outside our windows, blue-rich light is emitted in the morning, sending us alert signals as we wake up.

Even a windowless office or meeting room can mimic (or outperform!) the glow of the daylight outside. The lights can be programmed to provide high energizing blue and white light earlier in the morning, as the body naturally awakens and we get up and go. The lighting can then gradually shift to lower levels throughout the day. These subtle changes are usually invisible to our conscious selves, but they are relished by our subconscious circadian systems.

Our bodies’ photoreceptors, which pick up light, send signals to different parts of our brain and control different aspects of our bodily systems. The signals can “promote wellness, healing, a strong immune system, hormonal regulation, and metabolic functions,” according to USAI Lighting.

Research has shown that when we are denied our exposure to natural daylighting, our circadian system is disrupted, which then disturbs multiple other vital systems in our body controlling health, and specifically mental performance, productivity and irritability.

A new study published in the Cell Press journal Current Biology found that when mice were denied normal environmental rhythms and exposed to constant artificial lighting for over 5 months, their health drastically declined, including negative physiological changes, muscle loss, and osteoporosis. The constant artificial light exposure also reduced the normal rhythmic patterns in the brain’s central circadian pacemaker by 70 percent. However, when the standard light-dark cycle was restored, the negative effects were reversed.


“We used to think of light and darkness as harmless or neutral stimuli with respect to health,” said Johanna Meijer, Leiden University Medical Center in the Netherlands. “We now realize this is not the case based on accumulating studies from laboratories all over the world, all pointing in the same direction. Possibly this is not surprising as life evolved under the constant pressure of the light-dark cycle.”

Because of our increased understanding of the impact of light on our health, circadian lighting design is already codified within sustainable building performance standards. The WELL Building Standard acknowledges and awards points for projects with these lighting systems. WELL is one of the first rating systems to value lighting’s influence on circadian rhythm above and beyond typical lighting standards.

According to the WELL standard, “Insufficient illumination can lead to a drift of the circadian phase, especially if paired with light trespass at night. Lower levels of light during the day can also cause drowsiness, especially in the afternoon. The body requires both periods of brightness and darkness at appropriate points throughout the day to maintain optimal circadian rhythm.”


Circadian lighting might see the greatest impact within healthcare and senior living facilities where they are often brightly lit longer than necessary, and where wellness is paramount. We also see this taking off in the commercial office space – healthy, alert employees translate into a more productive, happy, and profitable workplace.

Is the light in your home or workplace significant to your well being? If all it takes is a little light to be more alert, energetic and all around healthy, let it shine!

Julia Raish Paladino and Company

Julia Raish is division leader at Paladino’s Seattle office. 

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