Researcher Jeffrey M. Burns, MD, says in a news release that Alzheimer's patients were also compared to those who did not have the disease.
"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, suggesting less brain shrinkage related to the Alzheimer's disease process in those with higher fitness levels," the researchers write.
The Alzheimer's group was looked at for how fit participants were within that group and also compared to a group with no dementia.
The participants were tested on treadmills to see what their peak oxygen consumption (also known as VO2) was. The VO2 is the standard used to measure cardiorespiratory fitness. They researchers used this measure to assess physical activity level. The participants were also given mental assessments and MRIs (magnetic reasoning imaging) to examine the gray and white matter in their brains.
Burns is with the University of Kansas School of Medicine. He says the results could show that exercise can be crucial to thinking clearly: "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 cites that other research in older adults who do not have Alzheimer's has shown that exercise can help keep the brain from changing because of aging.
The researchers say their study is one of the first to look at how physical fitness is related to Alzheimer's disease.
They urge more research because the results were based on taking the standard measure of fitness at just one time.
The study is published in the July 15 edition of Neurology.