Even Light Exercise May Drop Dementia Risk

Researchers look at whether light-intensity physical activity is associated with a lower risk of developing dementia.

LET’S CUT TO THE CHASE — a new study demonstrates an association between light-intensity physical activity in older adults and a lower risk of dementia. While the study does not establish causality between light exercise and lower dementia risk, it does add to a growing body of literature pointing to physical activity as beneficial for memory retention.

First, a brief look at dementia. We will then pivot to the new study results before ending with some potential risk-reducing maneuvers.

Dementia is not a single entity; instead, dementia is a grab bag descriptor for a range of conditions marked by cognitive impairment. Think problems with memory, thinking, or decision-making. Late in its course, dementia can reduce one’s awareness of the world. The most common form of dementia is Alzheimer’s disease.

Let’s be clear — while dementia is primarily (but not exclusively) a disease of older folks, it is not a part of normal aging. Unfortunately, Alzheimer’s disease gets progressively worse over time. Alas, there is no cure. The focus tends to be on symptom management.

Photo by Warren Umoh on Unsplash

Here are some of the risk factors for dementia, according to the United States Centers for Disease Control:

  • Age. The probability of developing dementia increases with age. Most cases of dementia are among individuals ages 65 years and older.
  • Inherited genetics. Individuals with parents or siblings with dementia are more likely to develop the condition.
  • Race and ethnicity. Older African-Americans are twice as likely to develop dementia than their white counterparts. Hispanic individuals overall have a 1.5-fold increased risk.
  • Poor heart health. One more reason to watch our blood pressure and cholesterol. Don’t even think about using tobacco.
  • Traumatic brain injury (TBI). Head injury can increase the risk of dementia, especially if the trauma is severe or repeated.

Light exercise and dementia

Let’s move on to our research investigation. Researchers looked at whether light-intensity physical activity is associated with a lower risk of developing dementia.

The investigators gathered data from over 62,000 subjects at least 65 years old, with a median age of 73.2 years. None had dementia, and all had medical records in the Korean National Health Insurance Service database.

The study authors tracked physical activity at the study start, with participants completing a questionnaire. The scientists then examined the frequency, intensity, and duration of physical activity to calculate how much energy expenditure was due to physical activity.

After a median 42 months follow-up, the research findings are: Six percent of the subjects developed dementia. Looking by quartiles of activity (ranging from inactive to insufficiently active to active to highly active):

The insufficiently active individuals had a 10 percent lower risk of getting dementia compared with the inactive group members. The active participants had a one-fifth drop in risk, and the highly active group had a more than one-quarter (28 percent) lower risk.

When adjusted for sex, age, and other medical conditions, the findings held.

Takeaway messages

Light-intensity physical activity (as opposed to being sedentary) is associated with a lower probability of developing dementia. While the study is well-done and is in line with the results of other studies, the results are not evidence of a causal relationship between light-intensity exercise and a lower risk of dementia. The reverse may be true — those developing exercise may exercise less.

I am encouraged by this type of study. Some believe that lifestyle may prevent approximately one-third of dementia cases. That’s the view of Professor Tara Spires-Jones of the University of Edinburgh (United Kingdom).

I will continue to walk (and more). Even though this new study adds to a growing body of evidence pointing to lifestyle influencing dementia risk, I know activities such as walking can help lower the risk of heart attack, stroke, cancer, and more.

Thank you for joining me today.


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Michael Hunter, MD
Michael Hunter, MD
I received an undergraduate degree from Harvard, a medical degree from Yale, and trained in radiation oncology at the University of Pennsylvania. I practice radiation oncology in the Seattle area.
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