Heart rate variability as a measure of disease state in irritable bowel syndrome.

Heart rate variability (HRV) is a noninvasive measure of sympathovagal balance in the autonomic nervous system (ANS). This review will: (a) consider HRV measurement in irritable bowel syndrome (IBS); (b) discuss the applicability of HRV measurement in IBS by addressing strengths and limitations; and (c) propose future directions in this field of gastrointestinal research and clinical practice. As a strength, analyzing HRV components is a useful method and appears most suitable for detection of changes in ANS sympathovagal balance in both stress and non-stress conditions with good validity and reliability. Also, it is an appropriate measure for ANS in studies with large populations, in both laboratory and clinical settings, and for longitudinal studies because of its noninvasive assets. With regard to limitations of measuring HRV, these are poor standardization, additional human editing, not considering medication or other confounding factors, inconsistent results in gastrointestinal vagal tone study, and different time periods.