Lots of excellent points from everyone... Thank you!
Confession: The main reason I still run and mainly bicycle ride, ever since I retired from the Coast Guard back in the late 90's is due to the fact that my dad passed away in 2002 from congestive heart failure. Now, now, now, I don't want to get all weird or say anything extremely improper, but, you'd have to understand my dad... WWII Army/Air Corps vet, big barrel chested man, 6'3" 250 lbs, senior electronics engineer from IBM. He retired from IBM in 1977 after 30 years. Anyway, when he retired, that was it. He just....retired.... He didn't go out and play golf, didn't bicycle ride, didn't run or jog, didn't do anything. Absolutely zero physical activity for the next 20+ years. He just stayed in his workshop piddling around with electronic circuit boards, capacitors, transistors, etc... and fixed TV's and radios for people. When he died, I was absolutely devastated as you can imagine... I am the "baby" of the family at 57 and the only boy with 4 older sisters. He was all I had to look up to as a kid aside from two older vietnam vet brothers-in-law.
Anyway, I don't want to end up like my dad, so I do whatever I have to do in order to keep my cardio-vascular system in shape. I run, bicycle ride, play golf, swim, etc... and am involved in countless other activities. But getting back on point, I truly enjoy riding my classic '85 Fuji road bike a lot more than running 4 or 5 miles!