Cumulative effect of all exercise that I’ve done over the years on my health
ATTITUDES TOWARD EXERCISE AND AGING have changed dramatically in recent decades, as shown by 73-year-old Ed Whitlock’s record-setting sub-three-hour marathon in 2004. His time of 2:54:48 wasn’t just fast for an old guy—he placed 26th out of more than 1,400 finishers. The aging body is capable of much more than we once believed, but study after study has shown that we have to “use it or lose it.” As a result, researchers are busy figuring out what kinds of exercise are best for keeping our bodies and minds young.
For athletes like Whitlock, though, the biggest question is not what exercise can do for their aging bodies, but what aging will do to their 5K times. “Masters” sport (often defined as over-40) is the fastest-growing segment of sport in North America, and the experiences of these remarkable athletes offer valuable lessons about how to stay motivated and adjust workout routines as we age.
What’s the cumulative effect of all the exercise I’ve done over the years?
Unless you make a dramatic turnaround after a severely misspent youth, it’s inevitable that some of your body parts won’t work as well in your 50s as they did a few decades earlier. It may be tempting to blame that on the punishment you’ve inflicted on your body during years on playing fields, ice rinks, and jogging paths—but the opposite is more likely. In fact, researchers have a good idea of the average rates of decline you can expect for various systems. And for almost every sign of aging you can think of—muscle loss, weight gain, artery hardening, joint stiffening—there have been studies suggesting that exercise slows it down.
It’s not just the obvious physical ailments that exercise fights off. Better circulation of blood to the brain helps delay mental decline, and at a microscopic level exercise appears to slow the aging of your cells. Some benefits aren’t yet fully understood, like the 2009 finding by Lawrence Berkeley National Labs researcher Paul Williams that aerobic exercise dramatically reduces the risk of glaucoma, macular degeneration, and cataracts. This may have something to do with links between cardiovascular fitness and fluid pressure behind the eye—but in a sense, it doesn’t really matter how it works. The important thing is that, thanks to epidemiological studies, we know that exercise is the most powerful anti-aging tactic we’ve got.
Of course, many competitive sports do result in some wear and tear, and a series of studies have connected sports like soccer and hockey to elevated risk of knee osteoarthritis in later life. More recent studies, though, have differentiated between the risk of simply playing these sports and the risk that arises from acute knee injuries. According to a Swedish study in 2006, the increased risk of arthritis for soccer and hockey players was entirely attributable to those who had suffered serious knee injuries during their playing career. Moreover, a 2008 study of former top-level Tunisian soccer players aged 45 and over who had never suffered acute knee injuries found that they had less knee pain and less functional disability than a group of matched controls.
If it’s acute injuries rather than wear and tear that lead to arthritis, you might expect running to be in the clear—and indeed that’s what a series of recent studies have concluded. Needless to say, this conclusion will be hard for many people to believe. After all, the aging runners they know are certainly subject to aches and pains. But the data collected by Williams and others suggest that, while everyone acquires aches as they age, it’s the people who don’t exercise who acquire the most. “As these runners aged,” Williams noted after one of his studies, “the benefits of exercise were not in the changes they saw in their bodies, but how they didn’t change like the people around them.”
Will running ruin my knees?
This is a fear that stops many would-be runners in their tracks and lurks in the back of the mind of even the most experienced. Occasional aches and pains are pretty much an inevitable part of running on a regular basis, so it’s entirely reasonable to wonder whether the exercise you’re enjoying now will leave you hobbling in a decade or two. Over the past few years, several long-term studies have produced results that should put these fears to rest.
In a 2008 issue of Skeletal Radiology, a team of Austrian radiologists presented knee MRIs of seven runners who had taken part in a previous MRI study before running the Vienna marathon in 1997. The use of MRIs offers a significant diagnostic advantage compared to earlier studies that relied on X-rays.
The results were clear: no new damage in the knee joints of the six subjects who had continued running in the intervening decade. “In contrast, the only person who had given up long-distance running showed severe deterioration in the intra-articular structures of his knee,” the authors note.
An even longer-term study at Stanford University has been following 45 runners and 53 non-running controls since 1984, taking regular X-rays. The latest results, which appeared in the American Journal of Preventive Medicine in 2008, showed that after 18 years, 20 percent of the runners had developed osteoarthritis (the most common form of arthritis) in the knee, compared to 32 percent of non-runners.
These two studies raise a possibility that several earlier studies have proposed: that, far from ruining your knees, running might actually help protect them. Due to the limited data available, it’s not possible to draw that conclusion at this point, Stanford lead author Eliza Chakravarty cautions. “I don’t think I would strongly recommend running for the purpose of ‘protecting the knees,’” she says.
Still, the idea is plausible: the American College of Sports Medicine recently reported that each additional pound of body mass puts four additional pounds of stress on the knee, so packing on a pound a year for a decade ups your chances of developing arthritis by 50 percent—a fairly powerful argument for running to protect your knees.
One important drawback with both studies is selection bias. The runners in both studies were committed recreational runners who already had a history of being able to run without serious problems. A more rigorous test would involve testing a random sampling of the general population, rather than pitting “runners” versus “non-runners.”
That’s effectively what researchers from the famously long-running Framingham Heart Study did, analyzing data from 1,279 subjects over a nine-year period and publishing the results in the journal Arthritis & Research in 2007. Using the comprehensive medical and lifestyle data accumulated for the study, the researchers found no association between exercise (including running) and the development of knee osteoarthritis.
Of course, the decision doesn’t have to be strictly utilitarian. As one of the Vienna study participants (who was preparing to run his 37th marathon) put it in an e-mail to lead author Wolfgang Krampla, “Even if minor aches and pains occur over the years, the gain in ‘joie de vivre’ far outweighs them.”