New Study Suggests Inactivity Among Seniors Increases Dementia Risk

Recent research underscores the idea that physical inactivity in older individuals might significantly raise their risk for dementia. The study examined nearly 50,000 British seniors, all of whom were 60 years or older. Their daily activity routines, tracked between 2006 and 2010, were then analyzed against dementia onset over a period of approximately seven years.

Professor David Raichlen of the University of Southern California, who spearheaded the study, shared a crucial observation: “If you’re sedentary for over 10 hours a day, there’s a higher risk [of dementia].” In fact, compared to being inactive for nine hours daily, seniors who were inactive for 10 hours had an 8% higher risk of developing dementia. Alarmingly, those who reported 12 hours of daily inactivity saw a 63% increase in dementia risk, and a staggering 320% increase was noted among those inactive for 15 hours daily.

However, it’s crucial to note that this study does not conclusively assert that inactivity directly causes dementia. It’s possible that underlying factors leading to inactivity, like deteriorating physical health or even undetected early stages of dementia, could be the actual culprits.

When asked why inactivity might be linked to a higher risk of dementia, Raichlen suggested, “It is possible that reduced blood flow to the brain can help explain these results.” He further indicated that inactivity is also tied to higher risks for cardio-metabolic diseases such as heart attacks, strokes, diabetes, and liver disease. Nonetheless, Raichlen emphasized the need for more research to clearly understand the association’s underlying mechanisms.

Interestingly, the participants, hailing from England, Scotland, and Wales, showed no initial signs of dementia when they enrolled in the study. Their activity levels were monitored using wrist activity trackers continuously for three to seven days between 2013 and 2015. By 2021, over 400 participants had been diagnosed with dementia.

Contrasting the findings with American lifestyles, the research team highlighted that Americans, on average, are sedentary for roughly 9.5 hours daily. This level of inactivity does not seem to correlate with an increased dementia risk. Yet, exceeding 10 hours of daily inactivity did suggest a heightened risk for seniors.

The million-dollar question remains: Can reversing years of inactivity reduce the risk? Raichlen expressed his personal sentiment, “In my opinion, it is never too late to sit less and move more.” However, he admitted the study’s limitations, stating the data doesn’t pinpoint any specific life phase where inactivity is more strongly linked to dementia risk.

Source:
Raichlen DA, Aslan DH, Sayre MK, et al. Sedentary Behavior and Incident Dementia Among Older Adults. JAMA. 2023;330(10):934–940. doi:10.1001/jama.2023.15231