Planners ask, manufacturers answer

The circadian rhythm is guided by the natural rhythm of light and darkness and determines our activity and sleep patterns.

Light regulates our waking and sleep patterns, which have evolved to match the 24-hour cycle of our environment. The circadian rhythm is what causes us to wake up when the sun rises and become sleepy as darkness falls. Responsible for this is the sleep-inducing hormone melatonin produced in the pineal gland, which is controlled by the hypothalamus. The hypothalamus responds to impulses received by non-visual photoreceptors within the eye.

As a result of our busy lifestyles we spend less time in natural light during the day, but instead are exposed to artificial lighting at night. This disrupts the body’s natural rhythm and can lead to sleeping disorders and serious conditions, such as depression. Good lighting should therefore follow the patterns and rhythms of natural light.