Could Exercise Decrease Risk of Cognitive Impairment?

Older adults who reported doing more leisure time physical activity (LTPA) had less decline in memory and thinking abilities than those who reported less activity, according to a new study.

As part of the Northern Manhattan Study, researchers ascertained LTPA at enrollment using a validated in-person questionnaire. They assessed cognition in participants in the Northern Manhattan Study MRI substudy using a standard neuropsychological examination (NPE) (n=1,228), and they performed a repeat exam 5 years later (n=876).
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The researchers summarized LTPA as the maximum intensity of any activity performed, classified as none to light intensity (physical inactivity) (90%) vs. moderate to heavy intensity (10%). They subcategorized NPE using standardized z scores over validated domains: processing speed, semantic memory, episodic memory, and executive function. The investigators used multivariable linear regression models to examine the association of LTPA with initial and change in cognitive performance, and they adjusted analyses for sociodemographics, cardiovascular disease risk factors, and MRI findings (white matter hyperintensity volume, silent brain infarcts, cerebral volume).

No/low levels of LTPA were associated with worse executive function, semantic memory, and processing speed scores on the first NPE. The associations were slightly attenuated and no longer significant after adjusting for vascular risk factors. Cognitively unimpaired participants reporting no/low LTPA vs. moderate/high levels declined more over time in processing speed (β=-0.231±0.112, p=0.040) and episodic memory (β=-0.223±0.117, p=0.057) adjusting for sociodemographic and vascular risk factors.

“This representative sample of urban US adults who were cognitively normal and reported moderate or high physical activity levels showed less cognitive decline than those who reported low activity levels,” said study author Clinton Wright, MD, MS, of the Leonard M. Miller School of Medicine at the University of Miami. “Clinical trials are needed to see if these benefits can be created through structured interventions.”

He said he’s currently working on a stroke trial where people are randomized to exercise plus cognitive training versus control conditions, noting this type of study could be applied to a more general population.

“Physical activity poses an attractive target for lessening the public health burden of cognitive impairment because of its low cost, lack of interaction with medications, and other health benefits,” the researchers concluded.

-Mike Bederka

Reference:

Willey JZ, Gardener H, Caunca MR, et al. Leisure-time physical activity associates with cognitive decline: The Northern Manhattan Study. Neurology. March 23, 2016 [epub ahead of print].