Every person has a personal biological clock. Many of us are unaware of this aspect of our life, and we ignore it, until... health problems start to appear. It looks like we, as humans, lost our touch with mother nature and we don't know how to be tuned into our bio-clock.Wild animals, on the other hand, seem to be in sync with their bio-clock and rarely get sick. Apparently, they know when to eat, when to sleep, and, while searching for food, they do a lot of workout. Except for the sloths, of course :D.There are many methods to calculate when it's a good time to do a sort of action such that we are in sync with our bio-clock. Our software uses one of them. We need your birth date to generate data for your bio-clock and your current location to calculate the sunrise and sunset. A 10km radius is good enough, so it is generally easier to locate the center of the city, this way you will not have to enter different values for home, work, gym or other places you might be going to.