How Much Exercise Is Really Necessary To Keep Dementia At Bay?

Hint: it’s rather less than the oft-recommended 150 minutes per week!

But that is still good though and that recommendation is still worthwhile. We often say “what’s good for your heart is good for your brain”, because the former feeds the latter (with oxygen and nutrients) and helps clear away detritus. It can’t do that without good circulation.

For that reason, we have written such articles as: What’s Your Vascular Dementia Risk? ← includes actual numbers and a risk calculator tool and things like that 😎

The threshold you want to meet

All so recently, researchers at the Texas Center for Community Health and Aging found that maintaining moderate regular activity lowered dementia risk in adults aged 50 and older.

How much is “moderate”, that’s so much less than the 150 minutes popularly recommended?

Will not keep you in suspense: per the study, at least 20 minutes of exercise twice-weekly appeared to slow dementia in older adults with mild cognitive impairment.

It was quite a big study; the team analysed data from 9,714 adults (average age 78), and assessed memory, working memory, and attention/processing speed. Of those in the study, 8% developed Alzheimer’s disease or dementia during the study period.

As Dr. Lee noted,

❝One out of every nine adults 45 and older in the United States say they experience confusion or memory loss that is getting worse.

Our age and how well our brain was working to begin with are factors. In addition, solving puzzles, spending time with others and staying physically active may help slow down or even stop the slide.

The benefits of exercise for this group have long been known, but by using a longitudinal study design and analyzing various levels of activity, we could determine the amount and duration needed to help prevent further decline.❞

About those numbers, and how the “20 minutes twice-weekly” was arrived at:

❝Individuals with a PA level of 2.80 experienced a 4.6% reduction in the odds of developing AD/ADRD (B = −0.046, OR = 0.954, 95% CI, 0.946–0.964). Similar significant effects were observed at PA levels of 2.60, 2.40, and 2.20, with ORs of 0.962, 0.967, and 0.970, respectively, all within 95% CI. These findings indicate that maintaining a PA level between 2.20 and 2.80 is significantly associated with a reduced risk of AD/ADRD. Lower PA levels such as 2.00 (OR = 0.974, P = .09) and 1.80 (OR = 0.983, P = .06) showed nonsignificant trends toward risk reduction.❞

• PA = physical activity
• ADRD = Alzheimer’s disease & related dementias

Source: Longitudinal Estimation of Adequate Physical Activity Levels to Reduce the Risk of Alzheimer’s Disease and Other Dementias in Older Adults With Mild Cognitive Impairment

Translating those numbers from sciencese, it’s worth noting that while the PA levels (e.g. 1.80, 2.00, 2.20, 2.40, 2.60) look like ratios (wherein 2.0 would mean doing twice as much as the average person, with the average person definitionally scoring 1.0), they’re not.

In actual fact, they’re borrowed from the Health and Retirement Study (HRS) 2012–2020 survey instruments, whose questions ask how often participants do:

• vigorous activity
• moderate activity
• mild/low-intensity activity

For each, participants choose one of four frequency categories, which are numerically coded as follows:

1 = hardly ever / never
2 = one to three times per month
3 = once a week
4 = more than once a week

Which is how the “20 minutes (enough to count as having exercised if picking the most moderate exercise options), twice per week (incidence)” gets represented in numbers, as this maps neatly to the cutoff between PA level 2.0 (nonsignificant) and PA level 2.2+ (significant).

Since in numbers, this looks like:

• ≤ 2.0 represents mostly just monthly activity, thus no significant benefit
• ≥ 2.2 is at least weekly activity in multiple categories, thus a statistically significant benefit

So, get those two 20-minute walks in per week, and you’re hitting the minimum for significant brain benefits!

See also: How To Walk Away From Alzheimer’s

Want to do even better for your brain? Check out: Do Try This At Home: The 12-Week Brain Fitness Program (12 Weeks To Measurably Boost Your Brain)

You may be wondering what the strange-looking creature is in the image at the top of that article. No, not the neuroscientist, the other image, the cartoon. The clue is in its seahorse-like shape—it’s a hippocampus, best known for its role in memory! Training with weights in the cartoon there, which is not quite the way to train it in reality.

However! Training with weights (using your muscles) can actually improve brain health too; see: Can Strength Training Fight Dementia?

Want to learn more?

For a much deeper dive, you might like this book that we reviewed a little while back:

Healthy Heart, Healthy Brain: The Personalized Path to Protect Your Memory, Prevent Heart Attacks and Strokes, and Avoid Chronic Illness – by Dr. Amy Doneen & Dr. Bradley Bale

Take care!