There have been many, many studies on this matter over the past couple decades. A couple of my favorite meta-aggregators of these studies are Rogue Health and Fitness and Mark's Dailly Apple (yeah, he's a paleo advocate, but he's also a former top competitive runner, Ironman winner, and currently a sculpted buff dude in his 60s -- and his wife only a few years younger looks like a fitness model). Even more interesting, look into guys like Art Devany. He and his wife are in their mid-70s, yet fitter than most people in their 40s.
Basically, the health promises of the 70s-80s were found to be false along several axes. The most notorious being recommendations for the low-fat, high-carb diet, but also the whole jogging/aerobics craze that started in the late 70s has been found to be empirically a failure. This is what led to the renewed interest in weight-lifting and other strength training. Long-duration, plodding exercise really isn't ideal to longevity. Running 10 miles a day used to be thought the peak of fitness, but really it results in muscle atrophy, heart strain, joint problems, etc...
And the problem with focusing on athletes is generally that they overdo it. Athletes are people singularly focused on *winning* not on health and longevity. Athletes will gladly trade a decade of life for a short-term competitive edge. This is what Mark Sisson (Mark's Daily Apple above) found. His competitive running had him constantly sick and/or injured. He scaled his workout way back, stopped the long-distance running, and focused more on short-duration high-intensity exercise to stimulate the hormesis/recovery cycle, and specifically worked on gaining muscle mass.
There is sort of a golden mean to exercise, recovery, muscle mass, strength, etc... And generally it looks about like the "fitness model" ideal for women and the wrestler physique for men. Muscular but not freakish. Slim but not skinny, low body fat, but not veins showing everywhere... you get the idea.
Side note: I was flying back from SCALE 13x last week, and ended up sitting next to a cardiologist who has been doing research in these areas. His synopsis: we should all be lifting weights, and lifting *heavy*.