Study uncovers a surprising temporal relationship between cognitive function and physical activity

The decline in cognitive abilities from the age of 50 is associated with a subsequent decrease in physical activity, which in turn is associated with greater depressive symptoms, according to new research published in translational psychiatry. The findings suggest, contrary to popular belief, that cognitive function is a stronger predictor of changes in physical activity than physical activity is a predictor of changes in cognitive function.

“Participating in regular physical activity and maintaining high cognitive function are essential for health,” the study author explained. Boris Chavalresearcher at the Swiss Center for Affective Sciences at the University of Geneva and author of “Le Syndrome du Paresseux” (The Sloth Syndrome).

“Therefore, age-related declines in physical activity and cognitive function often affect mental health. However, the nature of the relationship between physical activity, cognitive function and mental health throughout aging remains unclear.”

“Here, our goal was to determine whether physical activity or cognitive function mediated this relationship using a sophisticated statistical approach to answer this question,” explained the researcher. “Does physical activity precede change in cognitive function? Or does cognitive function precede change in physical activity?”

The researchers examined longitudinal data from 51,191 adults aged 50 years and older from more than 25 countries. The data comes from the Survey of Health, Aging and Retirement in Europe (SHARE), which started in 2004 and has collected information from participants approximately every 2 years. The survey asked, “How often do you do activities that require a low or moderate level of energy, such as gardening, cleaning the car, or walking?” It has also included assessments of depressive symptoms and cognitive functioning (memorizing 10 words and reciting them after a delay).

Cheval and colleagues found that higher cognitive function predicted higher physical activity 2 years later and higher physical activity predicted lower depressive symptoms 2 years later.

“Using a statistical method, we formally showed that a decline in cognitive function predicted a decline in physical activity, which in turn predicted a higher level of depressive symptoms,” Cheval told PsyPost. “So, in these data, cognitive function predicted decreased physical activity. In turn, the decrease in physical activity negatively affected people’s mental health.”

There was some evidence of a bidirectional relationship. The researchers also found that higher physical activity predicted higher cognitive function 2 years later, which was associated with fewer depressive symptoms. But the model with physical activity as the mediator fits the data better than the model with cognitive function as the mediator. In other words, cognitive functioning prevents inactivity more than physical activity prevents decline in cognitive functioning.

“The prevailing existing literature suggests that physical activity has strong positive effects on people’s cognitive health (which is the case also observed in the study),” Cheval explained. “However, the potential role of cognitive function in promoting participation in physical activity was largely overlooked (we saw only half the story).”

“Here, we show how cognitive function may be critical to promoting participation in physical activity (ie, a predictor) and not just a positive outcome that some may expect from regular participation in physical activity.”

“A plausible explanation for this observation that cognitive function predicts physical activity can be found in the effort minimization theory of physical activity (TEMPA)Cheval added. “Specifically, anchored in an evolutionary perspective of physical activity, TEMPA argues that people have an automatic tendency to minimize effort that may explain difficulty engaging in regular physical activity, a proposition that has been confirmed by a large number of studies. ”.

“Crucially, because of this automatic attraction to physical inactivity, TEMPA proposes that cognitive function is essential to counteract this attraction and thus favor participation in physical activity. Taken together, although not directly evaluated, the current findings fit well with TEMPA.”

The study, “Physical activity partially mediates the association between cognitive function and depressive symptoms“, was written by Zsófia Csajbók, Stefan Sieber, Stéphane Cullati, Pavla Cermakova and Boris Cheval.