We’re instinctively drawn to natural light. But our need for sunlight goes beyond our ability to see or feel its effect on our skin.
In the human eye, light is detected by specialised cells that send signals to the region of the brain responsible for vision. But these cells also send signals to the region of the brain that controls our biological clocks and circadian rhythms.
The human body is naturally programmed to function on a 24-hour internal clock that matches the solar day.
Known as the circadian rhythm, this clock is synchronized by light and controls many aspects of our physiology, metabolism, and behavior, including our sleep-wake cycle.
Melatonin is a hormone produced by the brain that plays an important role in the regulation of our sleep wake-cycle.
Melatonin production naturally starts to increase in the evening, peaks in the middle of the night; and rapidly declines in the morning, allowing us to wake-up.
Exposure to blue light or bright light before bedtime can lead to melatonin suppression, which can delay sleep onset and shorten sleep duration. Inversely, exposure to blue-enriched bright white light in the morning can have an energising effect.
Light sources can vary in terms of color, from warm (orange) to cool (blue), and in terms of intensity, from dim to bright. Lights of different colors and intensities will result in different responses from the brain.
Exposure to electric (static) lights can disrupt our natural circadian rhythms, which can directly affect our health and well-being.
Click on an image to experience different lighting intensities.