Go ahead and do crossword puzzles, eat nuts and fish, and use coconut oil in your cooking, but if you really want to fend off Alzheimer's disease and other forms of dementia, you can do nothing better than exercise every day, according to a new study.
Dr. J. Carson Smith of the University of Maryland School of Public Health has demonstrated that even older adults who already show signs of cognitive impairment improved their memory and brain function over 12 weeks simply by walking on a treadmill at a moderate pace for 30 minutes, four times a week.
"There may be multiple factors that combine to produce the improvement," said Smith, lead author of the paper.
Exercise contributes to the growth of new neurons in the hippocampus, the region of the brain associated with memory and the part Alzheimer's disease attacks first, Smith said.
"Exercise also promotes the growth of capillaries, which provide nutrients and energy to cells. And exercise may reduce inflammation, allowing the brain to function more efficiently," he said.
The study compared two groups of physically inactive older adults ranging in age from 60 to 88, who agreed to participate in the exercise plan, which was supervised by a personal trainer. One group contained 17 people diagnosed with mild cognitive impairment, or MCI. The other contained 18 people with no memory problems. The treadmill walking was adjusted for each participant, with the effort gradually increased over 12 weeks.
"We had them start at moderate intensity, which may have been 2 miles per hour for some, and gradually increased the speed and maybe the incline so they were doing a little more every week," Smith said. "The exercise got their heart rate up, and caused them to breathe a bit heavier, and sweat a little bit. They didn't report it as being unpleasant and they kept coming back. We had 96 percent attendance at the sessions."
Since one of the first symptoms of Alzheimer's disease involves difficulty remembering familiar names, the participants had their brains imaged while they attempted to identify photos of celebrities such as Frank Sinatra. The scanning was done both before and after the 12 weeks of exercise, and the brain scans showed a significant decline in brain activity in 11 brain regions, indicating greater efficiency of cognitive processing.
Also, participants improved on a test that involved reading a list of 15 words and remembering as many as possible, both immediately and after being distracted by another list of words.
Another study in which Smith participated, reported last year in the journal Current Alzheimer Research, found that moderate physical activity over 18 months reduced cognitive decline among older people who carry a gene for apolipoprotein epsilon 4 (ApoE4), the strongest known genetic risk factor for Alzheimer's disease. Cognitive stimulation activities alone had no effect.
Exercise certainly won't eliminate the mental decline that comes with age, but getting people already experiencing significant memory problems to improve their brain function and their ability to remember words "is a very big step in the right direction," Smith said.
Tom Valeo writes on health matters. He can be reached at firstname.lastname@example.org.