Never give up.  New research shows that, in people with serious heart failure, regular exercise strengthens the heart, generates new blood vessels, and produces new stem cells.

Physical activity strains the heart's arteries and muscles by sending 10 times the normal amount of blood to the muscles being used. Stem cells then are dispatched to relieve this stress and may repair any damaged parts. If you continue to exercise, these stem cells help the body adapt to the stress, by building new blood vessels and strengthening muscles. But to maintain such benefits, you must exercise regularly.