Heart rate variability improves in 3–5-year-old children following a 6-month physical activity-based intervention: the Active Early Learning (AEL) cluster randomised controlled trial. - Speer, Kathryn E.; McKune, Andrew J.; Telford, Rohan M.; Semple, Stuart; Naumovski, Nenad; Olive, Lisa S.; Telford, Richard D. (Applied Physiology, Nutrition & Metabolism, 2022)