Why do I get sleepy?

We’re all familiar with the sensation of sleepiness – heavy eye-lid, that warm, fuzzy feeling. But, one CrowdScience listener wants to know, what’s actually going on in our body and brain when tiredness takes over?Presenter Marnie Chesterton takes up the challenge and follows a trail that leads to circadian scientists working at the NASA Ames research centre in Silicon Valley. It turns out aviators and astronauts take sleepiness very seriously indeed.Marnie sends out roving reporter Anand Jagatia to investigate how our psycho-motor skills are affected by fatigue in a driving simulator. And we ask how does sleepiness change with age? Why, when tired, do adults crave a nap but children become ever more excitable? And what the hell’s going on with teenagers? We have some answers.Presented by Anand Jagatia Produced by Dom Byrne (Photo: Tired woman taking a nap at work sitting at office desk. Credit: Getty Images)