The Nature of Things - Season 52 Episode 5

Twelve hours of light. Twelve hours of dark. For our entire history we have lived and worked in rhythm with the sun. But all that changed with the invention of artificial light. Light fixtures, computer and television screens - all of these have allowed us more time to live, work, play and shorten our nights. But at what cost? Are we putting our health at risk? We explore how the type of light we are exposed to in the hours between dusk and bedtime can play tricks on our bodies and cancel the healthful benefits naturally triggered by the absence of light.