If you've spent a lifetime being a lazy bum, don't worry, all is not lost. You can undo the effects of being a couch potato, even if you've never worked out in your life. But, you really have to work out, hard.

A group of 50 people were given two separate work outs from a research group in Dallas. One was told do work on balance and flexibility, EG - yoga. The other was given a more intense work out including lifting weights and high-intensity interval training.

The group that had the high-intensity work outs showed signs of more flexible heart muscles in just two years. Flexible heart muscles is what you want because with age, your heart starts to tighten up, which leads to failure.

While the group that did yoga didn't show improvements in their heart, doesn't necessarily mean that yoga is bad for you. It just takes the more intense work out to help your heart. And there is a cut off to this as well. Research shows that by age 65, what's done is done and it's probably too late.