Running slows the aging clock, Stanford researchers find

STANFORD, Calif. — Regular running slows the effects of aging, according to a new study from the Stanford University School of Medicine that has tracked 500 older runners for more than 20 years. Elderly runners have fewer disabilities, a longer span of active life and are half as likely as aging nonrunners to die early deaths, the research found.

“The study has a very pro-exercise message,” said James Fries, MD, an emeritus professor of medicine at the medical school and the study’s senior author. “If you had to pick one thing to make people healthier as they age, it would be aerobic exercise.” The new findings appear in the Aug. 11 issue of the Archives of Internal Medicine.

When Fries and his team began this research in 1984, many scientists thought vigorous exercise would do older folks more harm than good. Some feared the long-term effect of the then-new jogging craze would be floods of orthopedic injuries, with older runners permanently hobbled by their exercise habit. Fries had a different hypothesis: he thought regular exercise would extend high-quality, disability-free life. Keeping the body moving, he speculated, wouldn’t necessarily extend longevity, but it would compress the period at the end of life when people couldn’t carry out daily tasks on their own. That idea came to be known as “the compression of morbidity theory.”

Fries’ team began tracking 538 runners over age 50, comparing them to a similar group of nonrunners. The subjects, now in their 70s and 80s, have answered yearly questionnaires about their ability to perform everyday activities such as walking, dressing and grooming, getting out of a chair and gripping objects. The researchers have used national death records to learn which participants died, and why. Nineteen years into the study, 34 percent of the nonrunners had died, compared to only 15 percent of the runners.

At the beginning of the study, the runners ran an average of about four hours a week. After 21 years, their running time declined to an average of 76 minutes per week, but they were still seeing health benefits from running.

On average both groups in the study became more disabled after 21 years of aging, but for runners the onset of disability started later.

“Runners’ initial disability was 16 years later than nonrunners,’” Fries said. “By and large, the runners have stayed healthy.”

Not only did running delay disability, but the gap between runners’ and nonrunners’ abilities got bigger with time.

“We did not expect this,” Fries said, noting that the increasing gap between the groups has been apparent for several years now. “The health benefits of exercise are greater than we thought.”

Fries was surprised the gap between runners and nonrunners continues to widen even as his subjects entered their ninth decade of life. The effect was probably due to runners’ greater lean body mass and healthier habits in general, he said. “We don’t think this effect can go on forever,” Fries added. “We know that deaths come one to a customer. Eventually we will have a 100 percent mortality rate in both groups.”

But so far, the effect of running on delaying death has also been more dramatic than the scientists expected. Not surprisingly, running has slowed cardiovascular deaths. However, it has also been associated with fewer early deaths from cancer, neurological disease, infections and other causes.

And the dire injury predictions other scientists made for runners have fallen completely flat. Fries and his colleagues published a companion paper in the August issue of the American Journal of Preventive Medicine showing running was not associated with greater rates of osteoarthritis in their elderly runners. Runners also do not require more total knee replacements than nonrunners, Fries said.

“Running straight ahead without pain is not harmful,” he said, adding that running seems safer for the joints than high-impact sports such as football, or unnatural motions like standing en pointe in ballet.

“When we first began, there was skepticism about our ideas,” Fries said. “Now, many other findings go in the same direction.”

Fries, 69, takes his own advice on aging: he’s an accomplished runner, mountaineer and outdoor adventurer.

Hanging on his office wall is a photo he jokingly describes as “me, running around the world in two minutes.” In the dazzling image of blue sky and white ice, Fries makes a tiny lap around the North Pole.

Fries collaborated with Stanford colleagues Eliza Chakravarty, MD, MS, an assistant professor of medicine; Helen Hubert, PhD, a researcher now retired from Stanford, and Vijaya Lingala, PhD, a research software developer.

The research was supported by grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases and by the National Institute on Aging.
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Exercise may prolong seniors' independence

BY EWEN CALLAWAY

Abby C. King

On your mark, get set, go! Seniors who acquaint themselves with that well-known mantra may live more independent lives, according to new research.

A study, which appears in the November issue of Journal of Gerontology, is the first to show that physical activity can improve a person's score on a standardized test of physical mobility, said Abby King, PhD, professor of health research and policy and of medicine at the Stanford Prevention Research Center. She and other Stanford researchers took part in the multicenter study demonstrating that elderly people who increase their levels of regular exercise perform better on a test measuring balance, walking speed and ability to rise from a chair.

Researchers at the University of Florida and the National Institute of Aging coordinated the work. The Stanford team, led by King, played a key role in recruiting and working with 100 study participants in the Bay Area, out of a total of 424 nationwide. The research was a preliminary study, and the next step is to conduct a full-scale, long-term trial on the benefits of exercise in the elderly.

"We are encouraged by these results, which demonstrate that a well-designed program combining aerobic, strength, balance and flexibility exercises can make a difference for those who are at high risk of losing mobility function," said Jack Guralnik, MD, PhD, a co-leader of the study from the National Institute of Aging.

King said the study sought to determine whether regular exercise could keep people healthier and more independent as they age. "The goal of this study is prevention—keeping people out of nursing homes," she said. "Exercise is one way of having a huge impact on our aging population."

According to King, earlier research had shown that seniors with lower scores die earlier and are also more likely to end up in assisted-care facilities. The participants in this study were aged 70 to 89 and lived independently, though they were at risk of developing an age-related disability, said King.

The study leaders randomly divided participants into two groups. Half the seniors spent approximately 2.5 hours a week walking at a moderate pace. They also strengthened and stretched their leg muscles. The second group of seniors received education on healthy living, including advice on nutrition, medication and foot care. The study followed participants for slightly more than a year.

The people who exercised regularly performed better on the standardized fitness test than people who received health education alone, and were better able to walk a quarter of a mile. The test is scored on a scale of one to 12, and the people who exercised upped their scores by one point on average, which is considered substantial. They were also less likely to suffer from an age-related disability that hampered their movement.

The findings held for men and women as well as for people of different ethnic backgrounds. Indeed, regardless of background, as people age, they share a concern. "When you ask seniors what they are most afraid of, they often don't put cancer or other specific age-related diseases at the top of the list," said King. "They say loss of independence."

The study was conducted at three centers besides Stanford—the Cooper Institute in Dallas, the University of Pittsburgh and Wake Forest University—and was funded by the National Institute on Aging. Investigators from Tufts, Yale, UC-San Diego, UCLA and the NIA also worked on the study.