Exercise in middle age may safeguard cognition in old age

By John Murphy, MDLinx
Published September 9, 2016

Key Takeaways

Vigorous physical activity during midlife was associated with a 50% lower risk of cognitive impairment in old age, according to a long-term study of 3,050 twins in the Finnish Twin Cohort, published online September 2, 2016 in the Journal of Alzheimer's Disease.

Even after adjusting for common risk factors such as midlife hypertension, smoking, education level, gender, obesity, and binge drinking, the association remained statistically independent, the researchers found.

“This suggests that the beneficial influence of physical activity on the brain and cognition is not solely based on decreasing vascular risk factors,” said lead author Paula Iso-Markku, MD, of the Department of Clinical Physiology and Nuclear Medicine at the University of Helsinki, in Helsinki, Finland.

For this study, participants in the Finnish Twin Cohort replied to questionnaires about physical activity in 1975 and 1981 (mean age in 1981: 49 years). Between 1999 and 2015, after an average follow-up of 25 years (mean age: 74.2), researchers evaluated the subjects’ cognition through validated telephone interviews. The researchers categorized participants as cognitively impaired, suffering mild cognitive impairment, or cognitively healthy.

“Few long-term, high-quality, follow-up studies on physical activity and cognition have been published, and it has remained unclear what type and amount of exercise is needed to safeguard cognition,” Dr. Iso-Markku noted.

This long-term study provided some answers. “Overall, the study shows that moderately vigorous physical activity, meaning more strenuous than walking, is associated with better cognition after an average of 25 years,” explained Urho Kujala, MD, PhD, Professor of Sports and Exercise Medicine at the University of Jyväskylä, Finland. “This finding is in accordance with earlier animal model studies, which have shown that physical activity increases the amount of growth factors in the brain and improves synaptic plasticity.”

However, the researchers found that the volume of physical activity did not reflect any further cognitive improvement in a dose-dependent manner. In other words, more exercise didn’t necessarily lead to better brain power later on.

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