As we gear up for BBC Music Day, Michael Mosley finds out whether singing can boost feel-good chemicals in the brain, Dr Zoe Williams discovers why music could help people with dementia, and Dr Alain Gregoire looks at some new research showing the surprising benefits of group singing for mothers with post-natal depression. Also in the programme, Dr Giles Yeo finds out whether 'man flu' is real, and Gabriel Weston asks whether detoxing is a con. Show less