As the age at which you finally get to retire from work increases, the more likely it is that you will want to do as little as possible once you finally get there. However, if you truly want to make the most of your retirement, there are significant mental and physical health benefits of staying as active as possible. Having lived through an unprecedented fitness revolution – the proportion of American adults taking up regular exercise grew from 24 percent in 968 to nearly 60 percent in 1984 – baby boomer tend to think they are more active than they actually are and underestimate the amount of time they spend…