Effects of yoga and mindfulness practices on the autonomous nervous system in primary school children: A non-randomised controlled study.

Abstract Objectives The present study examined the effects of a yoga and mindfulness-based programme on the autonomic nervous system of primary school children by using heart rate variability parameters. Design A two-arm non-randomised controlled trial compared an integrated yoga and mindfulness-based programme (16 weeks) to conventional primary school lessons. Setting Primary school classrooms and conference rooms. Interventions Participants were allocated to a 16-week integrated yoga-based programme or conventional school lessons. A subgroup was randomised to receive 24h electrocardiogram-recordings. Main outcome measures Heart rate variability indices were measured, both linear (time and frequency domain) and non-linear (symbolic dynamics, compression entropy), calculated from 30-minute extracts of Holter-electrocardiogram-recordings. Assessments were conducted at baseline and at the end of intervention. Results 40 participants (42.5% female) were included into the analysis of HRV. No significant changes in heart rate variability parameters were observed between the groups after 16 weeks. In the intervention group, a trend towards increased parasympathetic activity could be seen over time, although not significantly enhanced compared to the control group. Conclusion Results obtained here do not clearly show that children in German primary school settings benefit from an integrated yoga-based intervention. However, exploratory post-hoc analyses point interestingly to an increased nocturnal parasympathetic activity in the intervention group. Further studies are required with high-quality study designs, larger sample sizes and longer-term follow-ups.