A new study conducted by the Herbert Wertheim School of Public Health and Sciences shows human longevity at the University of California San Diego.
In the January 25, 2023 online edition of Alzheimer’s and dementia: Journal of the Alzheimer’s AssociationThe team reported that among women age 65 or older, every additional 31 minutes per day of moderate-to-vigorous physical activity was associated with a 21% lower risk of mild cognitive impairment or dementia. The risk also decreased by 33 percent with every additional 1,865 daily steps taken.
“Given that the onset of dementia begins 20 years or more before the onset of symptoms, early intervention to delay or prevent cognitive decline and dementia among older adults is essential,” said senior author Andrea Lacroix, MD, MD, Distinguished Professor in the College of Medicine. “. Herbert Wertheim School of Public Health and Human Longevity Sciences at the University of California, San Diego.
While there are several types, 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 are not as severe as dementia.
According to the United States 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 coexist with dementia and are more likely to develop it 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 slow or reverse it. There is no cure,” said Lacroix.
However, because few large studies have examined device measures of locomotion and sitting in relation to mild cognitive impairment and dementia, much of the published research on the association of physical activity and sedentary behavior with cognitive decline and dementia is based on self-reported measures, said first author, Stephen Nguyen, PhD, MPH, is a postdoctoral researcher at the Herbert Wertheim School of Public Health.
In this study, researchers sampled 1,277 women as part of two adjunct studies to the Women’s Health Initiative (WHI) – the WHI Memory Study (WHIMS) and the Objective Physical Activity and Cardiovascular Health Study (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.
The 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 could include housework, gardening or walking. Moderate to vigorous physical activity can include brisk walking.
Study results also showed that higher amounts of sitting and prolonged sitting were not associated with a higher risk of mild cognitive impairment or dementia.
This information has clinical and public health significance because there is so little published information about the amount and intensity of physical activity required to reduce dementia risk, 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 results for daily steps are particularly noteworthy because steps are being logged by a variety of wearable devices that are increasingly worn by individuals and are easily adoptable.”
The authors said more research is needed among large and diverse groups that include men.
Co-authors are: John Bellettiere, UC San Diego; Kathleen M. Hayden and Stephen R. Rapp, Wake Forest University School of Medicine; Zhongzi D, Fred Hutchinson Cancer Center; Priya Palta, Columbia University Irving Medical Center; Marcia L. Stefanik, Stanford University School of Medicine; Joan E. Manson, Harvard Medical School; and Michael J. Lamonte, University at Buffalo – State University of New York.
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).