Previous research has shown exercise can offer a mental boost. But the benefits vary: One person may improve cognitively and have improved memory, while another person may show little to no gain.
Limited research has been done on how a single round of physical activity may affect cognition and working memory specifically in older populations, despite evidence that some brain functions slip as people age.
Researchers wanted to learn how a single session of exercise may affect older individuals. They enrolled 34 adults between 60 and 80 years of age who were healthy but not regularly active. Each participant rode a stationary bike on two separate occasions with light and then more strenuous resistance for 20 minutes. Before and after each exercise session, each participant underwent a brain scan and completed a memory test.
In the brain scan, the researchers examined bursts of activity in regions known to be involved in the collection and sharing of memories. In the working memory tests, each participant used a computer screen to look at a set of eight young adult faces that rotated every three seconds, flashcard style, and had to decide when a face seen two “cards” previously matched the one they were currently viewing.
After a single exercise session, the researchers found in some individuals increased connectivity between the medial temporal (which surrounds the brain’s memory center, the hippocampus) and the parietal cortex and prefrontal cortex, two regions involved in cognition and memory. Those same individuals also performed better on the memory tests. Other individuals showed little to no gain.
The boost in cognition and memory from a single exercise session lasted only a short while for those who showed gains, the researchers found.
The participants also engaged in regular exercise, pedaling on a stationary bike for 50 minutes three times a week for three months. One group engaged in moderate-intensity pedaling, while another group had a mostly lighter workout in which the bike pedals moved for them.
Most individuals in the moderate and lighter-intensity groups showed mental benefits, judging by the brain scans and working memory tests given at the beginning and at the end of the three-month exercise period. But the brain gains were no greater than the improvements from when they had exercised a single time.
“The result that a single session of aerobic exercise mimics the effects of 12 weeks of training on performance has important implications both practically and theoretically,” the authors write.
The researchers note their study had a small participant pool, with a homogenous population that excluded anyone with chronic health conditions or who were taking beta-blockers.
To address those limitations, the researchers expanded their participant pool in a five-year study to confirm their initial findings and learn more about how exercise alters older people’s brains.
The National Institute on Aging, part of the National Institutes of Health, funded the research.