A study from Switzerland’s Université de Genève looked to answer the question of which came first: a decrease in physical activity or cognitive decline?
Cognitive abilities and physical activity are correlated and the World Health Organization reported 3.2 million people a year die due to physical inactivity. However, researchers at UNIGE have sought to discover whether cognitive decline or physical inactivity influences the other. The study was published in the American Psychological Association's monthly peer-reviewed journal, Health Psychology.
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“Correlations have been established between these two factors, particularly in terms of memory, but also regarding the growth and survival of new neurons,” said Boris Cheval, a researcher at UNIGE’s Swiss Centre for Affective Sciences (CISA) in a press release. “But we have never yet formally tested which comes first: does physical activity prevent a decline in cognitive skills or vice versa? That’s what we wanted to verify.”
Earlier studies have hypothesized that physical activity prevents cognitive decline. But according to Cheval, recent studies may indicate that past research has “only told half the story... since they demonstrate that our brain is involved when it comes to engaging in physical activity.”
Researchers at UNIGE tested the two possible options by using data from the Survey of Health, Aging and Retirement in Europe, a socio-economic database covering more than 25 countries across the continent.
Over the course of 12 years, 105,206 adults ranging in age from 50 to 90 were tested every two years on their cognitive abilities and their physical activity.
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Researchers measured cognitive abilities with a verbal fluency test that saw participants name as many animals as they could in 60 seconds. They also tested cognitive ability with a memory test where they memorized 10 words before reciting them. Physical activity was measured using a scale from 1 to 4. A 1 indicated participants “never” engaged in physical activity while a 4 meant they were physically active “more than once a week.”
Then, the data was employed in three statistical models. The first reviewed whether or not physical activity predicted changing cognitive skills over time. The second looked at whether cognitive skills predicted the change in physical activity over a time period. Finally, the third looked at cognitive skills and physical activity in both directions.
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The study found that the opposite of what past studies concluded was true — cognitive abilities mostly influence physical activity, not the other way around.
“Obviously, it’s a virtuous cycle, since physical activity also influences our cognitive capacities. But, in light of these new findings, it does so to a lesser extent,” Boisgontier said.
“This study backs up our theory that the brain has to make a real effort to get out of a sedentary lifestyle and that by working on cognitive capacities, physical activity will follow,” Cheval said in the conclusion.
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