Active Voice: Do Skillful and Fit Kids Have Smarter Brains?
By Eero A. Haapala, Ph.D., and Timo A. Lakka, M.D., Ph.D.
Eero A. Haapala, Ph.D., is an adjunct professor of pediatric exercise physiology and a postdoctoral researcher at the Faculty of Sport and Health Sciences, University of Jyväskylä in Finland. He also has an appointment with the Institute of Biomedicine, School of Medicine at the University of Eastern Finland. His research focuses on the associations of physical activity and fitness with brain health and learning. Dr. Haapala has been a member of ACSM since 2013.
Timo A. Lakka, M.D., Ph.D., is a professor of medical physiology at the Institute of Biomedicine, School of Medicine at the University of Eastern Finland. He is also a specialist in internal medicine. Dr. Lakka’s research focuses on the prevention of major chronic diseases across the lifespan by increasing physical activity and improving diet.
This commentary presents Dr. Haapala’s and Dr. Lakka’s views on the topic of a research article which they and their colleagues had published in the March 2019 issue of Medicine & Science in Sports & Exercise® (MSSE).
In a Systematic Review published in 2016, ACSM suggested a positive association between physical fitness, cognitive functions and academic achievement in children. Although interest has increased in whether improving movement skills, increasing aerobic fitness and decreasing body fat percentage may enhance cognitive functions, most studies on this topic have been cross-sectional and do not allow firm conclusions about cause and effect regarding these relationships.
One hypothesis has been that improved physical fitness is neuroprotective so that it increases functional connectivity between brain areas, increases cerebral blood flow, improves neural vitality and survival and, therefore, improves cognitive functions. However, there is no consensus on whether improvement in physical fitness or decrease in adiposity is necessary to elicit cognitive benefits of exercise training. Some researchers also have hypothesised that the relationship between physical fitness and cognitive functions is neuroselective. That concept supposes that children with better cognitive functions choose a lifestyle leading to better movement skills, aerobic fitness and lower body fat content.
In our two-year longitudinal study, as presented in the March 2019 issue of MSSE, we examined how motor skills, aerobic fitness and body fat percentage were associated with cognitive functions in pre-pubertal children. Altogether, 371 pre-pubertal children performed field tests for movement skills, a maximal cycle ergometer exercise test for aerobic fitness, dual energy X-ray absorptiometry scans for body composition, and Raven’s Progressive Coloured Matrices for cognition at baseline and after two years of follow-up.
First, we asked whether changes in movement skills, aerobic fitness and body fat percentage were related to changes in cognition during two-year follow-up; however, we found no link between these parameters. Second, we investigated the associations of movement skills, aerobic fitness and body fat percentage at baseline with cognition scores at follow-up and observed that aerobic fitness at baseline was negatively associated with cognition two years later. However, this relationship was largely attenuated once cognition score at baseline was controlled. Moreover, neither movement skills nor body fat percentage at baseline were independently associated with cognition at follow-up.
Finally, we studied whether children at the sex-specific tertiles for scores in movement skills, aerobic fitness and body fat percentage at baseline differed in cognition over the two-year follow-up. Through these analyses, we found that boys in the two highest tertiles of movement skills at baseline had better cognition over the two-year period than boys in the lowest tertile. However, no such difference was observed in girls.
Surprisingly, we found no association of aerobic fitness or body fat percentage with cognition. These observations suggest that aerobic fitness and adiposity, although they are important determinants of cardiometabolic health in later life, may not be the primary predictors for cognitive development in children.
Cognitive performance is an important prerequisite for learning and academic achievement. Since we found a positive relationship between movement skills and cognition, we propose that movement skills can be used in screening children who may need special support in school.