November 29th, 2010
02:45 PM ET
Three studies presented Monday at the Radiological Society of North America’s annual meeting use imaging techniques to show how exercise can affect our bodies and brains.
Walking may slow cognitive decline in adults diagnosed with mild cognitive impairment and Alzheimer’s disease, as well as benefiting brains of healthy adults.
In an ongoing 20-year study, participants are monitored for the distance they walk each week, and their brain volume is measured using MRI, combined with mental function testing, using the 30-question mini-mental state exam, which measures cognitive decline. Researchers are following 426 people, which includes 299 healthy adults and 127 cognitively impaired adults, including 83 with mild cognitive impairment and 44 with Alzheimer’s disease.
"Volume is a vital sign for the brain," according to lead study author Cyrus Raji, Ph.D., from the University of Pittsburgh in Pennsylvania, "When it decreases, that means brain cells are dying. But when it remains higher, brain health is being maintained."
Participants walked between zero and 300 blocks per week. The researchers say greater amounts of walking were associated with greater brain volumes, especially in the key memory and learning areas of the brain. People with cognitive impairment needed to walk at least five miles – about 58 city blocks - per week to slow cognitive decline and maintain brain volume. Healthy adults needed to walk about six miles per week—at least 72 city blocks—to maintain brain volume and reduce their risk for mental decline.
"Alzheimer's is a devastating illness, and unfortunately, walking is not a cure," Raji said, in an RSNA press release, "But walking can improve your brain's resistance to the disease and reduce memory loss over time." Alzheimer’s affects as many as 2.4 million to 5.1 million Americans, according to the National Institute on Aging.
What’s the best way to prevent osteoarthritis—the most common type of arthritis that causes pain, swelling, reduced motion in the joints, and breaks down cartilage in the joints? Participating in light exercise, as well as avoiding frequent knee-bending activities, may help protect people at risk for osteoarthritis from developing it.
University of California, San Francisco researchers recruited 132 study participants who were at risk for knee osteoarthritis but were not yet experiencing symptoms. They also enrolled 33 control subjects in the study. Participants were separated into groups based on their responses to a quiz on physical activity and strength training. Exercise levels included sedentary, light exercisers, and moderate to strenuous exercisers. Strength training groups included none, minimal and frequent. Participants were also asked about knee bending activities they participated in, including walking up flights of stairs, lifting objects weighting more than 25 pounds, squatting, kneeling or deep knee bending.
Using MRI images, the researchers found that light exercisers had the healthiest knee cartilage of all exercise groups, and people with minimal strength training had healthier cartilage than those that did no strength training or frequent strength training. High-impact exercise, such as running for more than one hour per day, several times a week, was associated with greater risk for developing osteoarthritis, according to lead study author Dr. Thomas M. Link, M.D., of UCSF. Maintaining a healthy weight and avoiding high impact activities also reduce risk to knee damage, according to Link.
Participating in a two month ultra-long-distance running event may not be on your “to do” list, the participants in one such race showed German researchers some important physical effects of running that can be applied to marathon and even recreational runners.
Recruiting 44 runners participating in the nearly 2,800 mile TransEurope-FootRace in 2009, researchers spent two months collecting and analyzing MRI images, urine, blood and biometric data.
Another finding was that some leg injuries are safe to “run through” without stopping, such as intermuscular inflammation in the upper or lower legs. But injuries such as joint inflammation, carry more risk of worsening. Schutz noted "The rule that 'if there is pain, you should stop running' is not always correct."
The RSNA meets in Chicago, Illinois, through Friday.
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