Influence of physical activity and acute exercise on cognitive performance and saliva testosterone in preadolescent school children

Abstract

Background : We investigated whether the habitual physical activity (PA) level had an impact on the acute effects of a short bout of 12 minutes of intensive exercise on cognitive performance and testosterone (T) concentration in primary school children. We further looked for associations between the T concentration and cognitive performance. Methods : 42 students of a fourth grade (9–10 years of age) were randomly assigned to an experimental group (EG, n=27) and a control group (CG, n=15). The first saliva collection took place after a normal school lesson in which the students filled out a habitual physical activity questionnaire and completed the d2-test, a test of selective attention (pre-test). While the intervention (12 min) the EG performed an intensive exercise at a heart rate (HR) of 180–190 bpm and the CG participants watched a non-arousing movie. Afterwards, saliva samples were taken and both groups again completed the d2-test (post-test). Saliva was analyzed for testosterone. The whole sample was divided in low- and high physically active subjects by a median split. A 2×2×2 mixed factor ANOVA design with repeated measures was used to test for differences. Analyses were controlled for sex and BMI. Results : After the intervention participants of the experimental group showed better performances in the d2-test of concentration compared to control. We further observed a significant group (EG, CG), test (pre, post), activity level (high, low) interaction indicating a different pre- to post-test development in T concentration for high- and low-active participants in the EG and CG. Post hoc pairwise comparisons revealed that after acute exercise the T concentration decreased only in habitually low-active children. Conclusions : The results indicate that the intensive exercise only interacted with the hypothalamic-pituatary-gonadal (HPG) axis in habitually low-active preadolescents, but had a beneficial effect on cognitive performance for all participants independent of their activity level.

Keywords

• testosterone
• acute exercise
• children
• school
• cognition
• physical activity