Doctors claim to have found the optimal amount of steps you need to walk a day to live a long and healthy life. The research builds on previous studies that that have linked walking to a longer lifespan. According to the latest study, the sweet spot is up to 10,000 steps, which experts say can reduce your risk of heart disease and early death. These benefits also extend to people who spend most of their day sitting down, suggesting that walking can offset the harms posed by a sedentary lifestyle. The study, published in the British Journal of Sports Medicine, found that every extra step above …