Respiratory Sinus Arrhythmia - Age Differences

Age Differences

RSA is very pronounced in children, but without sufficient cardiovascular exercise it gradually disappears as a person approaches their teenage years. Typically, expression of RSA decreases with age; however, adults in excellent cardiovascular health, such as endurance runners, swimmers, and cyclists, are likely to have a more pronounced RSA. Professional athletes typically maintain very high vagal tone and RSA levels. RSA also becomes less prominent in individuals with diabetes and cardiovascular disease.

In general, young children with a high vagal tone level present more positive psychophysiological, behavioral, and social performance, as well as predictive outcomes in mental, motor, and social skills. Heart rate variability has been linked to a wide array of variables, including: behavioral inhibition, sympathy, instrumental coping, attention, and temperament. But, while a higher vagal tone is typically indicative of more adaptive functioning, newborn infants with high baseline levels of vagal tone were found to be highly reactive and irritable. However, by the time infants reach five to six months, vagal tone was found to be positively related to interest and positive expressiveness, while negatively related to internalizing stress. This buffering effect continues well into adolescence; studies have found that high vagal tone in eight to twelve years olds buffers against intense verbal marital conflict. It is a very strong effect which has been shown to protect the child against some of the negative effects of parental alcoholism. With the exception of the neonatal, high baseline vagal tone levels in children lead to a variety of positive effects.