Circadian Rhythm

The so-called circadian rhythm is a living organism’s biological daily rhythm of approximately 24 hours, often referred to as the “human body clock.” Light plays an important role in this, as this rhythm describes the adaptations of life forms that are oriented toward the sun’s path. The term “circadian rhythm” comes from Latin and means something like “approximately”; it refers to the approximate length of the day, which can be quite subjective. The circadian rhythm is governed by the seasons as well as the alternation of day and night, and it regulates active and passive phases. Light thus plays a decisive role in determining the daily routine and, consequently, the circadian rhythm; however, a lack of daylight can also lead to significant disruptions. These can range from sleep or eating disorders to depression. A classic example is seasonal affective disorder (SAD), which is triggered by a lack of sunlight during the cold season but disappears again in the spring as the days grow longer. When using lamps for lighting, it is therefore particularly important to ensure natural light, such as bright light sources to make it easier to get up in the morning, daylight-like light colors during the day, or optimal illumination of the workspace. In the evening, on the other hand, warm or dimmed light is used to create cozy mood lighting. Circadian lighting aims to mimic sunlight throughout the day and dynamically adjust brightness.