Physical Activity and Academic Performance: Genetic and Environmental Associations

Abstract

Introduction: Physical activity and academic performance are believed to be associated. Though both traits are partially heritable, it remains unclear whether these traits also share a genetic and/or environmental background in common. We aimed to examine to what extent leisure time physical activity and academic performance share genetic and environmental effects from early adolescence to young adulthood.

Methods: Participants were Finnish twins (2543-2693 individuals/study wave) who reported their leisure-time physical activity at ages 12, 14, 17, and 24 yr. Academic performance was assessed with teacher-reported grade point averages at ages 12 and 14 yr and by self-reported educational levels at ages 17 and 24 yr. Bivariate quantitative genetic modeling at each age and between different ages was performed to decompose the trait correlation between academic performance and physical activity into genetic and environmental components.

Results: The trait correlations between leisure-time physical activity and academic performance were positive, but modest at most (rtrait = 0.08-0.22 in males, and 0.07-0.18 in females). The genetic correlations between leisure-time physical activity and academic performance were higher than the trait correlations (rA = 0.17-0.43 in males, and 0.15-0.25 in females). Common genetic influences explained 43% to 100% of the trait correlations. Environmental influences shared by cotwins between leisure-time physical activity and academic performance were also correlated (rC = 0.27-0.54 in males, and 0.21-0.69 in females) explaining 41% to 100% of the trait correlations. Unique environmental influences were correlated only in females (rE = 0.10-0.15).

Conclusions: Both common genetic background and shared family environment (i.e., familial background) partially account for the associations observed between leisure-time physical activity and academic performance. However, the estimates vary in magnitude by age.

Figure 1

The relative contributions of genetic and environmental factors to variances in leisure-time physical activity (LTPA) and academic performance (AP) with 95% confidence intervals in parentheses in males and females.

Figure 2

The statistically significant correlations between additive genetic and shared environmental factors for leisure-time physical activity (LTPA) and academic performance (AP) for the best fitting models at ages 12, 14, 17 and 24 in males and females. Line weights denote the strength of correlations: dashed thin line (--) denotes a correlation between 0 and ±0.19; solid thin line (−) denotes a correlation between ±0.2 and ±0.29; dashed thick line (--) denotes a correlation between ±0.3 and ±0.39; and solid thick line (−) denotes a correlation over ±0.4.