Older women were less likely to develop mild cognitive impairment or dementia if they engaged in more daily walking and moderate-to-vigorous physical activity, according to a new study led by the Herbert Wertheim School of Public Health and Human Longevity Science at the University of California, San Diego. .
“Given that the onset of dementia begins 20 years or more before symptoms appear, early intervention to delay or prevent cognitive decline and dementia among older adults is essential,” said senior author Andrea LaCroix, Ph.D. , MPH, Distinguished Professor at the Herbert Wertheim School of Public Health and Human Longevity Science at UC San Diego.
While there are many types, dementias are a debilitating neurological condition that can cause loss of memory, 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 dementias.
According to the US Department of Health and Human Services, dementia affects more than 5 million people in this country. This number is expected to double by 2050.
More women live with and are at greater risk of developing dementia than men.
“Physical activity has been identified as one of the three most promising ways to reduce the risk of dementia and Alzheimer’s disease. Prevention is important because, once dementia is diagnosed, it is very difficult to delay or reverse. There is no cure,” said LaCroix .
However, as few large studies have examined device measures of movement and sitting in relation to mild cognitive impairment and dementia, much of the published research on the associations of physical activity and sedentary behavior with cognitive decline and dementia is based on self-measures. -reported, said first author Steven Nguyen, Ph.D., MPH, postdoctoral fellow at the Herbert Wertheim School of Public Health.
For this study, researchers collected data from 1,277 women as part of two ancillary studies of the Women’s Health Initiative (WHI) – the WHI Memory Study (WHIMS) and the Objective Physical Activity and Cardiovascular Health (OPACH). The women wore research-grade accelerometers and went about their daily activities for up to seven days to get accurate measurements of physical activity and sitting.
Activity trackers showed that the women averaged 3,216 steps, 276 minutes of light physical activity, 45.5 minutes of moderate to vigorous physical activity, and 10.5 hours of sitting per day. Examples of light physical activity might include housework, gardening, or walking. Moderate to vigorous physical activity can include brisk walking.
Study results also showed that a greater amount of sitting and prolonged sitting were not associated with a higher risk of mild cognitive impairment or dementia.
Together, this information has clinical and public health importance, as there is little published information about the amount and intensity of physical activity needed to lower the risk of dementia, Nguyen said.
“Older adults can be encouraged to increase movement of at least moderate intensity and take more steps each day to reduce the risk of mild cognitive impairment and dementia,” Nguyen said.
“The steps-per-day findings are particularly notable because steps are recorded by a variety of wearable devices increasingly used by individuals and can be readily adopted.”
The authors said more research is needed among large diverse populations that include men.
Coauthors include: John Bellettiere, UC San Diego; Kathleen M. Hayden and Stephen R. Rapp, Wake Forest University School of Medicine; Chongzhi Di, Fred Hutchinson Cancer Center; Priya Palta, Columbia University Irving Medical Center; Marcia L. Stefanick, Stanford University School of Medicine; JoAnn E. Manson, Harvard Medical School; and Michael J. LaMonte, University at Buffalo — SUNY.
This research was funded, in part, by the National Institute on Aging (P01 AG052352, 5T32AG058529-03) and the National Heart, Lung, and Blood Institute (R01 HL105065). The Women’s Health Initiative was funded by the National Heart, Lung, and Blood Institute (75N92021D00001, 75N92021D00002, 75N92021D00003, 75N92021D00004, 75N92021D00005).