Revisited: Saunas and cold plunges, where does the evidence stand?

In this episode from January 2026, Ian Sample puts listeners’ questions about dreams and nightmares to Dr Michelle Carr, the director of the Dream Engineering Laboratory in Montreal’s Centre for Advanced Research in Sleep Medicine, and the author of the book Into the Dream Lab. They look at why we dream, what we can learn by examining our dreams, and what we can do when dreams turn into nightmares. Carr gives her top tips for taking charge of our dreams and trying to influence their content. Help support our independent journalism at theguardian.com/sciencepod

Science correspondent Nicola Davis investigates the strange story of Tam O’Braan and his attempts to grow tea in Scotland. In episode three of this mini-series first broadcast in October 2025, all of O’Braan’s lies come to a head and it is revealed where he was sourcing the tea being supplied to hotels and shops. At trial, O’Braan takes the stand and the Scottish growers finally get some answers. But what remains today of the Scottish tea industry that O’Braan instigated?. Help support our independent journalism at theguardian.com/sciencepod

Science correspondent Nicola Davis investigates the strange story of Tam O’Braan and his attempts to grow tea in Scotland. In episode two of this mini-series first broadcast in October 2025, Nicola hears how O’Braan’s network of Scottish tea growers began to have suspicions about exactly what he was selling and where it came from, and how cutting-edge science helped provide some answers. Help support our independent journalism at theguardian.com/sciencepod

Science correspondent Nicola Davis investigates the strange story of Tam O’Braan and his attempts to grow tea in Scotland. In episode one of this mini-series first broadcast in October 2025, Nicola looks back on her first meeting with O’Braan while working on a feature about tea plantations in the UK. He was selling his award-winning Scottish-grown tea to some of the UK’s finest hotels, but something didn’t quite add up. And Nicola wasn’t the only person taking an interest in his story. Help support our independent journalism at theguardian.com/sciencepod

The first person has been treated with a highly anticipated new gene therapy that aims to turn back the clock on ageing cells. The trial is aimed at retinal cells, with the hope that encouraging them to behave as if they were young again could improve sight in the affected patients. If it proves to be safe, it could open the door to a whole raft of therapies based on the emerging field of cellular rejuvenation. To understand more about this cutting edge research, Madeleine Finlay hears from science editor Ian Sample and from Paul Knoepfler, professor of cell biology and human anatomy at the university of California, Davis.. Help support our independent journalism at theguardian.com/sciencepod