Our sleep-wake cycle is determined by our circadian rhythm, the body's internal 24-hour clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. The term circadian comes from the latin word 'circa diem' which means 'around a day' and exists in all types of organisms. 

The circadian rhythms throughout the body are connected to a master clock, located in the brain. For all you science lovers, our body's internal clock is found in the suprachiasmatic nucleus (SCN), which is in a part of the brain called the hypothalamus. At different times of the day, clock genes in the SCN send signals to regulate activity throughout the body controlling sleep and wake cycles, productivity and alertness, body temperature and the digestive system. Light is the most powerful influence on circadian rhythms as the SCN is highly sensitive to different hues of light that coordinate internal clocks in the body. What this means is that during daylight hours the light exposure causes the master clock to send signals to generate alertness keeping us awake and active. As the light begins to fall and night starts approaching the master clock initiates the production of melatonin, a hormone produced that promotes sleep, transmitting signals that help us stay asleep during the night. If we throw our circadian rhythms off balance, by not being exposed to enough bright light during the day, for example, it may cause feelings of sleepiness and lethargy which is definitely not how you want to feel during office hours.

Our modern lives are spent mostly indoors, so it is imperative we keep close ties to the sun, and its daily cycle, to maintain overall wellness. In order to do this our circadian rhythm must be in sync with our built environment, which is where the importance of design comes in. 

Designing with Circadian Health in Mind:

1. Maximise exposure to natural light:
Maximising our exposure indoors to natural light is one of the best ways to regulate our circadian rhythm. There are ways to enhance the exposure to natural light within a space through well-thought-out space planning. Using reflective surfaces and textures in the correct place in a room optimises natural light especially if they are positioned near a window to catch the angle of light and bounce it throughout the room. Designing open-plan spaces with the use of glass partitions is another great way to ensure natural light exposure from the building windows is able to beam through the entire space.

2. Using circadian electric lighting:

Circadian lighting is the concept that electric light can be used to support human health by minimizing the effect of electric light on the human circadian rhythm. Research has shown that long-term exposure to certain wavelengths of blue light at a specific intensity can have a negative impact on melatonin production. The circadian lighting system implements three approaches to best replicate the natural circadian. 

Intensity tuning: This involves a fixed colour temperature that is adjusted through a controlled dimming system to match the time of day.

Colour tuning: This involves changing the light intensity to mimic day/night time hours experiencing cooler colours in the morning and warmer colours in the evening.

Stimulus tuning: More accurate matching of the daylight spectrum replacing 'bad blue' lighting with 'good blue' light wavelengths.

3. Understanding the occupant's schedule and use of room space:

Understanding the inhabitants' use within the space can largely benefit where it is crucial to have light exposure. To then design main work areas to be rich in natural light or blue-rich light to synchronise or provide an alerting effect. 

Designing with circadian health in mind helps occupants maintain a normal sleep schedule and feel much happier and healthier. Read more about the importance of sleep for our overall well being. To find out what makes our designs 'Remarcable' check out our learn page  where we highlight our expertise in designing for wellbeing including well thought out lighting systems that sync with our circadian rhythms.