The UK’s favourite fitness coach is back with series three of his podcast. This summer, Joe will be speaking to inspirational friends and some of his favourite people to ask them what they do to keep themselves feeling mentally and physically strong in the face of life’s little challenges. It might be starting the morning in an ice bath or cosying up with a good book; every guest will share the one thing that works for them in the hope it might inspire you to try something new. This week, Joe is finding out more about sleep: something which Joe has come to understand as the foundation of everything else in life: eating healthily, exercising regularly, and helping with relationships and stress. Joe discusses all of this and much more with the scientist Dr Matthew Walker. He’s the founder of “The Centre for Human Sleep Science” at the University of California and he wrote the bestselling book Why We Sleep. Together they chat about everything from how sleep affects diet and mental health, to what's going on in the brain when we dream, and Matt's top tips for better sleep. This is sunshine in a podcast. Joe Wicks is here for you, and he won’t stop until you’re fit and happy. Producer: Eliza Lomas Editor: Dimitri Houtart A BBC Audio Bristol production for Radio 4