Abstract

The supra-chiasmatic nucleus develops early in the gestational process, and circadian rhythms can be observed in new-borns. It connects to the retina, part of the eye that is sensitive to light, and to the pineal gland, which secretes what is often referred to as the “sleep hormone”, melatonin, which starts rising about few hours before a natural bedtime and signals sleep to the body. While not the only modulating factor of the circadian rhythm, light plays a major role in adjusting and synchronising the body’s clock. Light that emits short wavelengths, such as blue and blue-green light, versus longer wavelengths of orange or red light, asserts more of an effect on the circadian photoreceptor