Dr Michael Mosley meets extraordinary people who seem to defy ageing. He learns how meditation can help fight dementia and how people can sharpen their minds by being more like children. And can skydiving keep your brain young?

Dr Michael Mosley meets an 84-year-old ballerina who proves age is just a number. He also visits Okinawa in Japan and discovers the factors behind the islanders' low risk of heart disease.

Michael learns how we can keep our hearing, smell and vision super-sharp into old age. In Chicago, Michael meets an 86-year-old jazz musician, and discovers how playing musical instruments and singing can prevent the hearing loss.

Michael travels to Los Angeles to meet a 71-year-old great-grandmother with amazingly line-free skin, and in Sacramento, he learns about a study that reveals how chemicals in mangoes can visibly reduce wrinkles on our faces.

Michael meets an 86-year-old cyclist in the Surrey Hills who has the immune system of a 20 to 30-year-old. In Hong Kong, a scientist has discovered that the ancient practice of tai chi can be a better way of losing weight than more vigorous exercise.

Michael discovers advances at the frontier of medicine that are attempting to turn back the clock on ageing. In Tel Aviv, he undergoes hyperbaric oxygen therapy, which scientists claim can reverse ageing at a cellular level.