Sleep, autonomic control, and preterm birth—complex interrelationships with important health consequences

Abstract

Heart rate variability is now well-established as a means to assess autonomic nervous system (ANS) control by analyzing the beat-to-beat variability over time of consecutive heart beats. The R-R intervals are mathematically transformed and depicted as power spectra within different frequency domains. Low frequency reflects both sympathetic and parasympathetic activity, high frequency reflects parasympathetic activity, and total power reflects overall autonomic activity. These analyses have been applied to a wide range of clinical conditions, and investigators have studied maturation of ANS control in preterm and term infants, with some evidence of increased influence of the parasympathetic system early in life (Physiol Meas 2016;37:1436-46). Impaired control may extend later in life and may even be a risk factor for sudden infant death syndrome (Sleep 2015;38:1635-44). In this context the work in this volume of The Journal by Thomas et al adds to the literature and raises an equal number of questions. In a population with sleep-disordered breathing (SDB) studied at ages 3-12 years (mean 6 years), those born preterm had evidence of higher parasympathetic activity than did matched term-born children, and this relationship was more pronounced with more severe SDB. The cause is not yet known, whether this represents the consequences of increased work of breathing, altered ANS maturation, or something else. It's also uncertain in which direction the relationship develops, whether dysregulated ANS control exacerbates SDB or the other way around. This work should lead to further investigations into the relationship of the ANS with development, and the consequences for long-term health. In this referred population, an obvious question is whether there are similar differences during wakefulness. Long term outcomes also need to be studied. This is a rich area for investigation, with the potential to identify not only the mechanisms by which adverse health outcomes develop, but potentially interventions to mitigate them. Article page 83 ▶ Cardiovascular Autonomic Control Is Altered in Children Born Preterm with Sleep Disordered BreathingThe Journal of PediatricsVol. 206PreviewTo assess if the effects of sleep disordered breathing (SDB) on heart rate (HR) and HR variability, as a measure of autonomic control, were more severe in a group of children born preterm compared with a group of children born at term referred to our sleep laboratory for assessment of SDB. Full-Text PDF