Horne RSC, Sakthiakumaran A, Bassam A, et al. - Since children with Down syndrome (DS) are at elevated risk for sleep disordered breathing (SDB), researchers sought to compare the cardiovascular effects of SDB in children with Down syndrome (DS) to those of typically developing (TD) children with and without SDB. Forty-four DS children (3–19 years) were age and sex matched with 44 TD children without SDB (TD−) and with 44 TD children with matched severity of SDB (TD+). The results show significantly decreased parasympathetic activity (reduced HF power) and increased LF/HF (a measure of sympathovagal balance) in children with DS, together with greater exposure to hypoxia, indicating that SDB has a higher impact on these children, which may lead to an increased risk of cardiovascular adverse events.