Public Release: 

Burning more calories linked with greater gray matter volume, reduced Alzheimer's risk

University of Pittsburgh Schools of the Health Sciences

PITTSBURGH, March 11, 2016 - Whether they jog, swim, garden or dance, physically active older persons have larger gray matter volume in key brain areas responsible for memory and cognition, according to a new study by researchers at the University of Pittsburgh School of Medicine and UCLA.

The findings, published today in the Journal of Alzheimer's Disease, showed also that people who had Alzheimer's disease or mild cognitive impairment experienced less gray matter volume reduction over time if their exercise-associated calorie burn was high.

A growing number of studies indicate physical activity can help protect the brain from cognitive decline, said investigator James T. Becker, Ph.D., professor of psychiatry, Pitt School of Medicine. But typically people are more sedentary as they get older, which also is when the risk for developing Alzheimer's disease and other dementias increases.

"Our current treatments for dementia are limited in their effectiveness, so developing approaches to prevent or slow these disorders is crucial," Dr. Becker said. "Our study is one of the largest to examine the relationship between physical activity and cognitive decline, and the results strongly support the notion that staying active maintains brain health."

Led by Cyrus Raji, M.D., Ph.D., formerly a student at Pitt School of Medicine and now a senior radiology resident at UCLA, the team examined data obtained over five years from nearly 876 people 65 or older participating in the multicenter Cardiovascular Health Study. All participants had brain scans and periodic cognitive assessments. They also were surveyed about how frequently they engaged in physical activities, such as walking, tennis, dancing and golfing, to assess their calorie expenditure or energy output per week.

Using mathematical modeling, the researchers found that the individuals who burned the most calories had larger gray matter volumes in the frontal, temporal and parietal lobes of the brain, areas that are associated with memory, learning and performing complex cognitive tasks. In a subset of more than 300 participants at the Pitt site, those with the highest energy expenditure had larger gray matter volumes in key areas on initial brain scans and were half as likely to have developed Alzheimer's disease five years later.

"Gray matter houses all of the neurons in your brain, so its volume can reflect neuronal health," Dr. Raji explained. "We also noted that these volumes increased if people became more active over five years leading up to their brain MRI."

He added that advancements in technology might soon make it feasible to conduct baseline neuroimaging studies of people who already have mild cognitive impairment or who are at risk for a dementia disorder, with the aim of prescribing lifestyle approaches such as physical activity to prevent further memory deterioration.

"Rather than wait for memory loss, we might consider putting the patient on an exercise program and then rescan later to see if there are any changes in the brain," Dr. Raji said.

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Other members of the research team include Kirk I. Erickson, Ph.D., Oscar L. Lopez, M.D., H. Michael Gachi, Ph.D., and Lewis Kuller, M.D., Dr.P.H., all of the University of Pittsburgh; David A. Merrill, M.D., Ph.D., Harris Eyre, M.D., Sravya Mallam, B.S., Nare Torosyan, B.S., and Paul M. Thompson, Ph.D., all of UCLA; Owen T. Carmichael, Ph.D., of University of California, Davis; and W.T. Longstreth, Jr., M.D., of the University of Washington.

The research was supported in part by funds from contract numbers N01-HC-80007, N01-HC-85079 through N01-540 HC-85086, N01-HC-35129, N01-HC-15103, N01-541 HC-55222, N01-HC-75150, N01-HC-45133 and grant HL080295 from the National Heart, Lung, and Blood Institute, with additional contribution from the National Institute of Neurological Disorders and Stroke.

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 1998. In rankings recently released by the National Science Foundation, Pitt ranked fifth among all American universities in total federal science and engineering research and development support.

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 http://www.medschool.pitt.edu.

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