Can't remember where you left your keys? Walking just six miles a week can ward off cognitive decline, says Jenny Hope.Walking is the best medicine to slow the progression of Alzheimer’s – and cut your risk of getting it, claim researchers.They prescribe five miles of walking a week to reduce the chances of the disease getting worse.Healthy people should walk six miles to reduce their chances of developing it, says a new US study.It found regular daily walking strengthens the brain’s memory circuits and also helps people who are starting to become forgetful. Read m...