Effects of Varying Type of Physical Exercise on Children's Salivary Cortisol

PURPOSE: Aim of this study was to investigate whether different physical exercise conditions could induce different exercise-related changes on children's salivary cortisol. METHODS. Saliva collection of 48 children (8-11 years of age) took place before (Pre) and after (Post) 50 min of a traditional physical education (TPE) and of a coordinative physical education (CPE) lesson, respectively. Physical education (PE) sessions occurred at the same time (in the morning) of the same school day over 2 weeks. The school day was planned to have the same schedule every day during the experimental intervention with PE lessons preceded by academic classes. During the TPE lesson, children were instructed to exercise at a moderate to vigorous physical activity (MVPA corresponding to HR > 139 bpm) intensity without any specification on motor coordination. The CPE lesson, conducted at the same exercise intensity, was characterized by a high variability of motor coordination and skill learning demands. RESULTS. Results showed that participants' salivary cortisol was significantly affected by Time (Pre vs Post) (5.51 + or - 4.50 nmol/L vs 4.01 + or - 2.70 nmol/L, F= 5.74; p=0.02), indicating a reduction of salivary cortisol after the two PE lessons independently of their content (F=1.01; p=0.32). CONCLUSION. We found that varying types of physical exercise did not differently affect children's salivary cortisol concentration. Moreover, a significant decrease of the cortisol concentrations occurred from pre- to post-exercise. Our findings suggest that physical education could act as a distractor, leading to a reduction of school stress. These activities were probably enjoyable and relaxing for children and in turn cortisol decreased.