Fitness May Protect the Brain in Early Alzheimer's

GETTING PLENTY of exercise may help keep your brain fit. New research at the University of Kansas finds that people with early Alzheimer's disease who did best on a treadmill test were also less prone to the brain atrophy associated with the disease.

The study, published in Neurology, used the treadmill to measure peak oxygen consumption — a gauge of cardiorespiratory fitness — and MRI imaging to view the brains of 57 patients with early Alzheimer's and a control group of 64 people free of dementia. After controlling for age, higher peak oxygen consumption was associated with greater whole brain volume as well as the volume of white matter, the core surrounded by the brain's "gray matter."

According to study author Jeffrey M. Burns, MD, "People with early Alzheimer's disease who were less physically fit had four times more brain shrinkage when compared to normal older adults than those who were more physically fit."

While the study represented only a snapshot in time, and thus can't prove a cause-and-effect relationship, it aligns with other research connecting fitness with slower cognitive decline. "We know physical activity helps with depression in Alzheimer's patients, and the general health benefits extend to those with Alzheimer's disease," Dr. Burns said.

It's normal for the brain to shrink with aging, but the shrinkage rate doubles in Alzheimer's patients. Dr. Burns added, "People with early Alzheimer's disease may be able to preserve their brain function for a longer period of time by exercising regularly and potentially reducing the amount of brain volume lost. Evidence shows decreasing brain volume is tied to poorer cognitive performance, so preserving more brain volume may translate into better cognitive performance."

The study did not, however, find an association between fitness and better performance on 15 standard cognitive tests. Dr. Burns speculated that too few subjects were included for significant statistical results.

The Kansas researchers also presented findings, not yet published, at an Alzheimer's Association international conference specifically linking fitness to better brain volume in areas important to memory. "We're able to locate the changes associated with fitness to the actual memory region, the hippocampus, which is a key area for Alzheimer's-related atrophy," said Robyn A. Honea, PhD, who led the second study.

Sam Gandy, MD, PhD, chairman of the association's Medical and Scientific Council, commented that the study's message is essentially that even if you already have Alzheimer's disease, you can still benefit from physical activity.

TO LEARN MORE: Neurology, July 15, 2008; abstract at . Alzheimer's Association, (800) 272-3900, .

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