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Moderate Physical Activity Linked to Lower Dementia Risk in Older Adults
A recent study conducted by researchers at the Johns Hopkins Bloomberg School of Public Health indicates that even minimal movement can significantly reduce the risk of developing dementia among older adults, including those who may be frail.
The study revealed that participating in just 35 minutes of moderate to vigorous physical activity weekly correlated with a 41% decrease in dementia risk over an average follow-up period of four years, compared to those who did not engage in any physical activity. This correlation holds true even for frail older adults, indicating that increased physical activity is beneficial regardless of one’s baseline health condition.
As the researchers examined the data, they discovered that greater levels of physical activity were associated with progressively lower risks of dementia. Specifically, participants who engaged in 35 to 69.9 minutes of physical activity per week exhibited a 60% reduction in risk. Following that, those in the 70 to 139.9 minutes per week category had a 63% lower risk, and individuals who exercised for 140 minutes or more each week experienced a 69% decrease in dementia risk.
This analysis was based on data from nearly 90,000 adults in the United Kingdom who wore activity trackers similar to smartwatches. The findings were published online on January 15 in the Journal of the American Medical Directors Association.
Lead author Amal Wanigatunga, PhD, MPH, suggests that incorporating even brief periods of physical activity can make a difference in reducing dementia risk for older adults. Wanigatunga, who is an assistant professor in the Bloomberg School’s Department of Epidemiology and a core faculty member at the Johns Hopkins Center on Aging and Health, emphasizes the growing evidence that even small amounts of exercise can contribute positively to brain health in aging populations.
Dementia, frequently associated with Alzheimer’s disease, is prevalent among older adults, affecting approximately seven million people in the United States. It’s estimated that around one-third of individuals aged 85 and older have some form of dementia. While the likelihood of developing dementia increases with age, recent research suggests that lifestyle modifications—including improved management of cholesterol, blood pressure, blood sugar, and increased physical activity—may mitigate this risk.
Despite the study’s encouraging outcomes, the specific volume of physical activity necessary for a meaningful reduction in dementia risk remains ambiguous. Many older adults, particularly those in fragile health, find it challenging to meet the higher exercise thresholds recommended by health authorities, which suggest 150 minutes of moderate-intensity exercise weekly, averaging 20 minutes per day.
For this study, Wanigatunga utilized data from the UK Biobank, an ongoing research effort involving around 500,000 participants. The analysis focused on 89,667 adults, primarily aged 50 and over, who tracked their physical activity via wrist-worn accelerometers from February 2013 to December 2015. Following an average of 4.4 years of health monitoring, 735 participants were diagnosed with dementia.
The research compared those who logged some amount of moderate to vigorous physical activity each week against individuals who were inactive, while adjusting for factors like age and existing medical conditions. Notably, individuals in the lowest activity category (1 to 34.9 minutes per week) demonstrated a significant risk reduction of approximately 41%.
When examining the subgroup of participants identified as frail or pre-frail, the relationship between increased physical activity and reduced dementia risk was unchanged, indicating that even those with diminished health status can benefit from lower-intensity exercise.
Although this study does not establish a causal link between exercise and reduced dementia risk, it aligns with growing hypotheses surrounding the importance of physical activity. To explore further, researchers conducted additional analyses excluding dementia diagnoses from the initial two years of follow-up, reinforcing the robustness of the association between increased physical activity and a diminished risk of dementia.
Wanigatunga and colleagues advocate for future research to delve into the impacts of low-dose exercise as a viable strategy to prevent dementia. With the support of the National Institute on Aging for this study, the findings contribute to an evolving understanding of how physical activity can play a crucial role in promoting brain health among older adults.
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