“Humans are the only species that willingly deprive themselves from sleep”. Ever since fire was discovered, we have traded off sleep time for other activities - from creating stone tools to partying. As our technology progressed, the list of things to do rather than sleep just got longer. But with sleep deprivation now a growing health problem, could we be reaching our limits? Or is tiredness part of our condition? In this week’s programme, an evolutionary biologist, a historian and a neuroscientist give us their take on whether we are now any more tired than our ancestors. We hear what makes human sleep unique and how it has evolved in surprising ways. And finally we hear from a woman with a dream – that we may never have to sleep again. Producer: Estelle Doyle and Sarah Shebbeare Presenter: James Fletcher (Photo: A woman shows signs of tiredness as she counts ballot cards. Credit: Leon Neal/Getty Images)