In 1960, Jim Brennan soared as an athlete. A world-class ski jumper, he tied the national distance record for ski jumping and represented the U.S. in the Winter Olympics in Squaw Valley, Calif.

Fifty years later, he’s still outdistancing his peers.

At 73, Brennan is more active than your average septuagenarian, often mountain biking, skiing or windsurfing with his wife, Dee.

“We do everything,” he said. “We still ski 100 days a year. I think any sport that somebody participates in, maybe not contact sports, it keeps you fit. It keeps you going. It keeps your mind moving.”

Studies show Olympic athletes enjoy a longer, healthier life than the average person. The question is why? Is it genetics, self-discipline or the affluence that can come with being an elite athlete?

Many researchers now believe it’s a much simpler explanation. These athletes live longer because, like Brennan, they tend to continue exercising throughout their lives. And if that’s true, it suggests even recreational athletes could enjoy an Olympic-sized advantage.

“The more you do, the better off you are,” Brennan said. “You have to get in shape and stay in shape and don’t ever get out of shape physically. It’s good for everything you do.”

Longevity dividend

A study published last year in the British Medical Journal tracked more than 15,000 Olympic medal winners from 1896 to 2010, matching the athletes with individuals from the general population by country, age and gender. They found that athletes lived, on average, 2.8 years longer than their non-Olympic counterparts.

“There are many possible explanations, including genetic factors, physical activity, healthy lifestyle, and the wealth and status that come from international sporting glory,” said Phillip Clarke, a professor of public health at Australia’s University of Melbourne and lead author of the study.

Olympic athletes may simply have a genetic advantage over the general population. The same genes that allow them to reach the pinnacle of their sports may keep them healthier over a lifetime. Elite athletes must also put in hours of training each day for years on end. They might also apply that same sort of discipline to other healthy behaviors, such as diet or not smoking, which in turn would affect their long-term health.

And certainly, being an Olympian helps in achieving a high socioeconomic status, which is one of the stronger predictors of better health.

But more fundamentally, researchers believe it is the cardiovascular exercise these athletes perform that conveys the greatest longevity benefit.

In 2010, Masaru Teramoto, an exercise physiologist with Drexel University, reviewed 14 research studies looking at the longevity of elite athletes. He found a correlation between sports that require higher amounts of cardiovascular fitness and longevity.

“Previously established evidence shows that any kind of physical activity involving aerobic exercise provides a great benefit in terms of preventing chronic disease, such as cardiovascular disease, cancer and so on,” he said.

Chronic disease, he said, is responsible for the majority of deaths in Western countries. Heart disease and cancer are each responsible for about 25 percent of deaths in the U.S. Stroke is No. 3 on the list. In fact, most of the Top 10 causes of death are chronic diseases, and almost all of them can be avoided or delayed through cardiovascular training.

“That’s the speculation why endurance exercise or aerobic exercise can provide a better benefit in terms of mortality and longevity,” Teramoto said.

Sport specifics

But you may not have to be a marathoner or a cross-country skier to experience those same gains. A second study published in the same issue of the British Medical Journal found that almost all Olympians lived longer, regardless of sport.

The researchers compared the longevity of Olympic athletes based on the cardiovascular intensity of their sport and found little difference. Athletes who competed in events such as golf or curling had just as big a longevity benefit as athletes in cycling or rowing.

The researchers did offer the caveat that athletes in sports with a high risk of bodily collision or with high levels of physical contact did not live quite as long as athletes in other sports. They suggested that could be the result of repeated injuries taking their toll over time. Boxers, for example, are at higher risk for cognitive impairment, early onset dementia and reduced life expectancy after enduring repeated blows to the head.

But studies show that even athletes in high-contact sports lived longer than the general population, just not as long as athletes from noncontact sports.

It’s unclear how much of an impact performance-enhancing drugs may have on the reduced longevity for athletes in such power sports. Weightlifters, like professional football and baseball players, have been linked to anabolic steroid use and other performance-enhancing drugs, which may dampen the benefits of their exercise.

Those offsets may eventually completely erode the gains from exercise. Much of the research has been done with athletes who competed early in the 20th century and have lived out their full lives. The impact of performance-enhancing drugs might not be seen until more recent generations of athletes reach old age.

Full-contact sports, such as football or hockey, have also changed significantly over the years. Advances in protective equipment have reduced the rate of certain injuries, but also allow for more violent collisions. And it’s not evident what effect that will have on the long-term health of athletes in such power sports.

In the end, however, the difference in longevity between power and endurance athletes may have less to do with their sports and more to do with their lifelong habits. Teramoto found that many of the power athletes didn’t maintain their fitness after they retired. Weightlifters and football players, he said, often became obese once they left their sports.

“They’re still pretty big and they minimized their exercise, so they tend to be more obese,” he said. “The endurance athletes, they tended to be physically active after their competitive career is over.”

Teramoto cautioned, however, that more research is needed to parse out these differences.

There are also unanswered questions about the amount of heavy training the body can tolerate. Some studies have shown that at extreme levels of cardiovascular exercise, there could be damage to the heart. A Swedish study in June found that cross-country skiers participating in 50-mile or longer races were at increased risk for developing irregular heartbeats. Still those skiers were considerably healthier and likely to live longer than the general population. And a number of cases of sudden death have been identified in long-distance runners.

It’s one of the questions Teramoto was most interested in exploring.

“It appears endurance exercise elite athletes still live longer than the general population, indicating that it’s probably OK, to engage in very competitive exercise,” he said. “But of course, there aren’t many Olympic-level (athletes), so the sample size is very small.”

Current exercise recommendations consider up to 300 minutes per week of exercise to be a safe level.

“Of course, the elite athletes train more than 300 minutes per week — pretty much, as long as they are awake, they engage in training,” Teramoto said. “The upper threshold is pretty high, probably. The risk of heart failure or sudden cardiac arrest by very intense exercise seems to be very, very small. And we can minimize the risk of this by doing a proper warm up.”

If the true Olympic advantage is indeed linked to regular exercise rather than elite-level participation, it suggests that anyone could garner the same benefit.

A German study published last year in the Journal of Aging Research found that individuals who get at least 150 minutes of moderate exercise each week live anywhere from one- to seven-years longer than inactive persons.

In a commentary on the research, two public health professors, Adrian Bauman from Sydney University in Australia and Steven Blair, from the University of South Carolina, said the take-home message is that regular exercise could pay Olympic-sized dividends.

“Although the evidence points to a small survival effect of being an Olympian, careful reflection suggests that similar health benefits could be achieved by all of us through regular activity,” they wrote. “We could and should all award ourselves that personal gold medal.”