Very interesting article on the benefits of wellbeing lighting and that our internal clocks are not just regulated by our metabolism. Its actually much deeper, our internal clocks virtually control every aspect of our physiology and behaviour with a link to the Paleolithic or Stone Age period.
These internal rhythms synched to the solar days are called circadian rhythms, and the biological clocks that generate circadian rhythms are called circadian clocks. In mammals, the main biological clock is located at the base of the brain in the hypothalamus and comprises a paired cluster of about 20,000 nerve cells. If individuals are left in constant conditions such as a dark cave, then the internal circadian rhythms emerge—and they are not exactly 24 hours—hence the term, circadian. For example, if you were placed in a dimly lit cave for several weeks, your sleep-wake cycle might be about 24 hours and 15 minutes, but not precisely, 24 hours as it would be above ground where the circadian clock is being reset daily by exposure to light. However, exposure to artificial light at night can derail this system and cause havoc.