There’s a chill in the air as the winter months come around again. But the cold isn’t always something to fight or guard against. With a little bit of care, you can invite the cold into your life - with real benefits for health and mood. In each episode of this new podcast series, Dr Michael Mosley uncovers the science behind a different way you can harness the power of the cold, alongside the very latest research and atmospheric sound design. In this final episode, how keeping a colder bedroom can lead to better, deeper sleep - and how our sleep is affected by the changing climate. Guests: Kathryn Reid, research professor, Centre for Circadian and Sleep Medicine at Northwestern University, Illinois. Dr. Nick Obradovich, Laureate Institute for Brain Research, Tulsa, Oklahoma Series Producer, Sound Designer and Mix Engineer: Richard Ward Researcher: William Hornbrook Science Producer: Samantha Lewis Production Manager: Maria Simons Editor: Zoe Heron Specially composed music by Richard Atkinson (Mcasso) A BBC Studios production for BBC Sounds / BBC Radio