By SHAUN WOOLLER HEALTH CORRESPONDENT PUBLISHED: 21:01 EST, 27 February 2022 | UPDATED: 03:36 EST, 28 February 2022 Staying fit into middle age can reduce the risk of developing Alzheimer’s disease by up to a third, a study suggests. Even small gains in heart and lung health can be hugely beneficial. Analysis of 649,605 people with an average age...