Article Title: Significance of Respiratory Sinus Arrhythmia in Human Health and Disease
Author: Melvin F Simoyi
Published Date: April 12, 2019
By definition respiratory sinus arrhythmia (RSA) is the alternate increase in heart rate during inspiration and decrease in heart rate during expiration so that heartbeat is synchronized with respiratory rhythm [1-3]. The autonomic nervous system has been indicated to play a major role in the interaction of respiration and circulation to coordinate the events happening during RSA . Respiratory sinus arrhythmia has also been linked to serve as an index of cardiac vagal tone  and good health . This phenomenon that is RSA is observed in many species including human beings where RSA is found to be strongest (i.e. a larger difference between inspiration heart rate and expiration heart rate) in the young and fit meaning that professional athletes would generally be found to have a much greater RSA compared to the general population [3,5]. Conversely, lower RSA is linked to several human diseases and conditions shyness or reticence in toddlers , substance use disorder , stress , and autism spectrum disorder . Therefore, this review seeks to discuss the significance of RSA in human health and disease.