A recent NY times article spoke about the new link that has been made between people who have had heart attacks and the frequency that they partcipate in cardiac rehabilitation.  After a major cardiovascular event, people who partcipated more often in cardiac rehab sessions lived longer and had fewer re-occurences.  What does this mean for those who have not had any sort of heart problems?  It means that exercising frequently, in addition to dietary changes, can lead to a signifcantly lower chance of heart problems.  Not only that, but your quality of life will be much higher.  You will find that you have more energy, and will save money on your health care over the long haul.

http://newoldage.blogs.nytimes.com/2010/02/02/for-seniors-an-underused-heart-therapy-the-gym/