Moderate to vigorous exercise and daily walks can reduce the risk of developing dementia among senior women, according to a study by UC San Diego researchers published Wednesday.
In Wednesday's online edition of "Alzheimer's & Dementia: The Journal of the Alzheimer's Association," the team from UCSD's Herbert Wertheim School of Public Health and Human Longevity Science found that, among women 65 or older, each additional 31 minutes per day of moderate-to-vigorous physical activity was associated with a 21% lower risk of developing mild cognitive impairment or dementia. Risk was also 33% lower with each additional 1,865 daily steps.
"Given that the onset of dementia begins 20 years or more before symptoms show, the early intervention for delaying or preventing cognitive decline and dementia among older adults is essential," said senior author Andrea LaCroix, distinguished professor at the Wertheim School.
Dementia is a "debilitating neurological condition that can cause loss of memory, the ability to think, problem solve or reason." Mild cognitive impairment is an early stage of memory loss or thinking problems that is not as severe as dementia.
According to the U.S. Department of Health and Human Services, dementia affects more than five million people in this country, with that number expected to double by 2050.
More women live with and are at higher risk of developing dementia than men, the UCSD researchers said.
"Physical activity has been identified as one of the three most promising ways to reduce risk of dementia and Alzheimer's disease. Prevention is important because once dementia is diagnosed, it is very difficult to slow or reverse. There is no cure," LaCroix said.
Due to lack of scholarly studies on the issue, much of the published research on the associations of physical activity and dementia is based on self- reported measures, said first author Steve Nguyen, postdoctoral scholar at the Wertheim School.
For Wednesday's published study, researchers sampled data from 1,277 women. The women wore research-grade accelerometers and went about their daily activities for up to seven days to obtain accurate measures of physical activity and sitting.
The activity trackers showed the women averaged 3,216 steps, 276 minutes in light physical activities, 45.5 minutes of moderate-to-vigorous physical activity and 10.5 hours of sitting per day. Examples of light physical activity could include housework, gardening or walking. Moderate-to-vigorous physical activity could include brisk walking.
"Older adults can be encouraged to increase movement of at least moderate intensity and take more steps each day for a lower risk of mild cognitive impairment and dementia," Nguyen said. "The findings for steps per day are particularly noteworthy because steps are recorded by a variety of wearable devices increasingly worn by individuals and could be readily adopted."
The authors said further research is needed among large diverse populations that include men.
