The rediscovery of sunlight for health. We spend 90% of the day indoors. Until late in the evening, computers, smartphones, and televisions are predominantly using blue light waves. But what does this lifestyle actually do to our bodies? Renowned doctor Dr. Bauhofer has found in his patients that they artificially extend their days and live against their internal clocks - with sometimes serious consequences. Current studies show that a lack of natural light disrupts the biorhythm and can lead to various diseases such as depression, diabetes, obesity, and even heart conditions. In this guide, the physician and the journalist provide comprehensive insights: Alongside the latest findings on light therapy, they share the best tips for living in harmony with the internal clock.