Are physical activity interventions effective in reducing the risk of cognitive decline and/or dementia in adults?

Should I eat my vegetables? solve crossword puzzles? play Sudoku? brush my teeth left-handed? As millions of Americans approach old age, the search escalates for “magic bullets” to preserve brain health.

In our next series of blog posts, we will look at approaches to prevent cognitive impairment and/or dementia as well as the evidence (or lack thereof) for their effectiveness. Today, we will look at the effects of exercise on brain health.

In reviewing the relationship between exercise and brain health, we have the good fortune of referencing the World Health Organization’s (WHO) recently published guidelines for reducing cognitive decline.1

Physical activity interventions

Summary of recommendations

The WHO guidelines summarize multiple trials to conclude that there is moderate quality evidence showing that regular exercise lowers the risk of cognitive decline in healthy adults, as well as positive, but somewhat less robust, evidence that exercise reduces cognitive decline in individuals with mild cognitive impairment (MCI).

As with many other prevention strategies, this evidence suggests healthy life habits have greater benefits before a disease develops.

The guidelines conclude, unsurprisingly, that the health benefits of exercise generally outweigh the undesirable effects.

Physical activity should be recommended to adults with normal cognition
Source: Risk reduction of cognitive decline and dementia: WHO guidelines. (2019)
Physical activity may be recommended to adults with MCI to reduce the risk of cognitive decline
Source: Risk reduction of cognitive decline and dementia: WHO guidelines. (2019)

Recommendations on physical activity for adults 65 years and above

Exercise type

Available evidence on exercise type suggests aerobic exercise may be somewhat more beneficial for cognitive health than resistance training. Muscle strengthening and balance-enhancing activities further add to the benefits. Moreover, the WHO notes exercise’s wider range of benefits for cardiorespiratory, bone and behavioral health.


150 minutes of moderate exercise (or 75 minutes of vigorous exercise) per week is recommended for seniors, with necessary modifications as abilities and conditions allow.

What about puzzles and games?

A critique on computer-based cognitive-training software — commonly known as brain games — makes the case that exercise stands on firmer ground for maintenance of brain health.2 In the text, the authors state:

Physical exercise is a moderately effective way to improve general health, including brain fitness. Scientists have found that regular aerobic exercise increases blood flow to the brain, and helps to support the formation of new neural and vascular connections.

Physical exercise has been shown to improve attention, reasoning, and components of memory. All said, one can expect small but noticeable gains in cognitive performance, or attenuation of loss, from taking up aerobic exercise training.

In our next post, we will take a closer look at those brain games. In the meantime, take that long walk or bike ride.


  1. World Health Organization. (2019). Risk Reduction of Cognitive Decline and Dementia: WHO Guidelines. Retrieved June, 2019.
  2. A Consensus on the Brain Training Industry from the Scientific Community. (2014). Retrieved June, 2019, from

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About the author

Robert Cuyler, PhD

Robert Cuyler is a clinical psychologist with decades of clinical, management and consulting experience. He is a Clinical Advisor at BrainCheck and the chief clinical officer of Palo Alto Health Sciences. He previously served as the CEO of JSA Health Telepsychiatry and clinical advisor to MDLive/Breakthrough Behavioral. Dr. Cuyler received his Ph.D. in psychology from Louisiana State University and his postdoctoral fellowship from the Menninger Foundation.

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