Even 5 Minutes of Exercise May Lower Dementia Risk, Finds American Study

A new study led by researchers at the Johns Hopkins Bloomberg School of Public Health suggests that even a little movement, even as little as five minutes a day, can help prevent dementia, particularly for frail older adults.

The study found that engaging in just 35 minutes of moderate to vigorous physical activity per week—compared to no activity at all—was associated with a 41% lower risk of developing dementia over an average follow-up period of four years. Even among frail older adults, who face a higher risk of health complications, greater physical activity correlated with lower dementia risk.

The study also found that dementia risk continued to decrease with higher levels of physical activity. Compared to those who were completely inactive, individuals engaging in 35 to 69.9 minutes of weekly exercise had a 60% lower risk of developing dementia. Those in the 70 to 139.9 minutes/week category saw a 63% lower risk. Participants exceeding 140 minutes/week had a 69% lower risk.

"Our findings suggest that even small increases in physical activity — just five minutes per day — can lower dementia risk in older adults," said Amal Wanigatunga, PhD, MPH, the study’s lead author and an assistant professor at the Bloomberg School's Department of Epidemiology. "This adds to growing evidence that some movement is better than none, particularly when dealing with a brain disorder that currently has no cure," he noted.

For the study, researchers analysed data from nearly 90,000 adults in the UK Biobank, a large-scale health research initiative. Participants wore wrist-worn accelerometers to track their physical activity for one week between February 2013 and December 2015. Their health was monitored over an average of 4.4 years, until November 2021, during which 735 participants were diagnosed with dementia.

The study was published online on January 15 in the Journal of the American Medical Directors Association.