“We found that walking five miles per week protects brain structure over 10 years in people with Alzheimer’s aand MCI, especially in areas of the brain’s key memory and learning centers,” said lead investigator Cyrus A. Raji, Ph.D., who is in the combined M.D./Ph.D. program at Pitt’s School of Medicine. “We also found that these people had a slower decline in memory loss over five years.”
Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and cognitive skills. According to the National Institute on Aging, between 2.4 million and 5.1 million Americans have Alzheimer’s disease. Based on current population trends, that number is expected to increase significantly over the next decade.
In cases of MCI, a person has cognitive or memory problems exceeding typical age-related memory loss, but not yet as severe as those found in Alzheimer’s disease. About half of the people with MCI progress to Alzheimer’s disease. “Because a cure for Alzheimer’s is not yet a reality, we hope to find ways of alleviating disease progression or symptoms in people who already are cognitively impaired,” added Dr. Raji.
For the ongoing study, the researchers analyzed the relationship between physical activity and brain structure in 426 people, including 299 healthy adults (mean age 78), and 127 cognitively impaired adults (mean age 81), composed of 83 adults with MCI and 44 adults with Alzheimer’s dementia.
Patients were recruited from the Cardiovascular Health Study. The researchers monitored how far each of the patients walked in a week. After 10 years, all patients underwent 3-D MRI exams to identify changes in brain volume, which is a vital sign for the brain, noted Dr. Raji. “When it decreases, that means brain cells are dying. But when it remains higher, brain health is being maintained.”
In addition, patients were given the mini-mental state exam (MMSE) to track cognitive decline over five years. Physical activity levels were correlated with MRI and MMSE results. The analysis adjusted for age, gender, body fat composition, head size, education and other factors. The findings showed across the board that greater amounts of physical activity were associated with greater brain volume. Cognitively impaired people needed to walk at least 58 city blocks, or approximately five miles, per week to maintain brain volume and slow cognitive decline. The healthy adults needed to walk at least 72 city blocks, or six miles, per week to maintain brain volume and significantly reduce their risk for cognitive decline.
Over five years, MMSE scores decreased by an average of five points in cognitively impaired patients who did not engage in a sufficient level of physical activity, compared with a decrease of only one point in patients who met the physical activity requirement.
“Alzheimer’s is a devastating illness, and unfortunately, walking is not a cure,” added Dr. Raji. “But walking can improve your brain’s resistance to the disease and reduce memory loss over time.”
Co-authors of the study, which was funded by the National Institute on Aging, include Kirk Erickson, Ph.D., Oscar Lopez, M.D., James Becker, Ph.D., Lewis Kuller, M.D., Caterina Rosano, M.D., Anne Newman, M.D., M.P.H., H. Michael Gach, Ph.D., Paul Thompson, Ph.D., and April Ho, B.S., all from the University of Pittsburgh School of Medicine.
About the University of Pittsburgh School of Medicine
As one of the nation’s leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1997 and now ranks fifth in the nation, according to NIH data for 2008 (the most recent year for which the data are final).
Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region’s economy. For more information about the School of Medicine, see www.medschool.pitt.edu.