New research from Texas A&M University suggests that just 20 minutes of exercise, twice a week, may help slow cognitive decline in older adults at risk of dementia.

The study, led by Jungjoo Lee at the Center for Community Health and Aging, analyzed nearly a decade of data from the Health and Retirement Study (2012–2020), tracking 9,714 adults aged 50 and older. Published in the Journal of Physical Activity and Health, the research sheds light on the amount of physical activity needed to support brain health.

“The benefits of exercise for older adults have long been recognized,” said Lee. “By using a longitudinal study design and analyzing different levels of activity, we were able to determine the amount and duration necessary to help prevent further cognitive decline.”

Understanding Mild Cognitive Impairment

Mild cognitive impairment (MCI) involves noticeable changes in memory or thinking that do not yet interfere with daily life. While not everyone with MCI develops Alzheimer’s or other dementias, those with the condition are at a higher risk.

“Some individuals with MCI remain stable or even improve over time, while others progress to dementia,” Lee explained. “Factors such as age, baseline brain health, and engaging in mentally and socially stimulating activities, including physical exercise, can help slow or even prevent further decline.”

The Link Between Activity and Cognitive Health

The researchers assessed cognitive function using memory recall, working memory, and attention/processing speed tests, then correlated results with engagement in 21 types of physical activity, ranging from walking to sports.

The study found that older adults who maintained moderate activity levels had a significantly lower risk of developing dementia over time, while those who were less active saw little to no benefit.

“Maintaining even modest levels of physical activity can make a meaningful difference in protecting cognitive health,” said co-author Junhyoung Kim.