Look at it this way: if you don't walk at least 15,000 steps a week, you can expect your lifespan to shorten by 3 years on average. 15,000 steps is in the realm

Look at it this way: if you don't walk at least 15,000 steps a week, you can expect your lifespan to shorten by 3 years on average. 15,000 steps is in the realm of bare minimums.