A new study is challenging one of the most pervasive messages in health and fitness: the belief that 10,000 daily steps are needed to prolong life and prevent disease. Led by Professor Melody Ding at the University of Sydney and published in The Lancet, the study is the largest of its kind, analyzing data from more than 30 studies worldwide. Its findings suggest that significant health benefits may be achieved with as few as 7,000 steps a day—an attainable target for many who find 10,00...