54|CUADERNOS The influece of natural light in the biological clock Our body behaves in different ways according to the time of day, controlled by what is known as the biological clock. However, the biological clock started breaking down as soon as humans controlled light. With the technological and social evolution, people’s living conditions have changed but our body has not adapted yet. T he most accepted theory of the origin of the universe is the Big Bang Theory, a great explosion that created the Universe, as we know it today, approximately 13.500 million years ago. The planets, stars and other celestial bodies emerged from this explosion. I am not going to go into the whole theory but to begin this article, I would like to bring to your attention a phenomenon: the Earth and the rest of the planets orbit around the Sun and at the same time they rotate on their axis. This rotation is what generates the night/day cycle. It has been going on since Earth was formed some 4.500 millions of years ago. My point is, that everything that has happened in our planet since it was formed has adapted to this night/day cycle. All living things have evolved as a consequence of this cycle: plants, for example, with photosynthesis, generate oxygen during the day in the presence of light and invert the process in the dark. Humans, as living beings, are not strangers to this phenomenon and they too, have adapted to this cycle all through their evolution, adapting their bodies to the available light in the environment and behaving in different ways according to this ambient lighting. It has been this way for the hundreds of thousands of years of evolution. Our body behaves in different ways according to the time of day and that is what is known as biological clock. Autonomously, and all through the thousands of years of evolution, human beings have adapted their body to this phenomenon. However, at a certain point in history, an event that would have a big impact on this process took place: the discovery of artificial light. The first evidence of the control over fire dates 1.5 million years ago. The first lamps where burning sticks or vessels full of embers. Later, torches that La relación entre la iluminación y la salud de las personas centrará de la próxima edición de Light + Building, que se celebrará del 30 de marzo al 4 de abril de 2014 en Frankfurt, Alemania. Fuente: Licht.de