Autonomic response to exercise as measured by cardiovascular variability

Motivation. There is growing interest in the use of cardiovascular variability indicators as measures of autonomic activity, even though reported results are not always comparable or as expected. This review aims to determine the consistency of results reported on the autonomic response to physical exercise as measured by heart rate variability, blood pressure variability and baroreceptor sensitivity. Method. An Ovid MEDLINE Database search for the period 1950 - March 2008 produced 46 articles for review. The published articles that evaluate the effect of exercise on the autonomic nervous system (ANS) are summarised in three categories: the response of the ANS during a bout of exercise, directly after exercise (recovery measurements), and after a long-term exercise programme. Results. Articles on the effect of training on the ANS as measured by cardiovascular variability indicators show increased variability, decreased variability, and no change in variability. Conclusion. Findings in this review emphasise that standardisation and refinement of these measuring tools are essential to produce results that can be repeated and used as reference. Standardisation is essential as these measurements are increasingly employed in studies regarding investigations of central autonomic regulation, those exploring the link between psychological pro cesses and physiological functioning, and those indicating ANS activity in response to exercise, training and overtraining. This review shows that important aspects are inter-individual differences, duration and intensity of the exercise programme, and choice and specific implementation of variability analysis techniques. South African Journal of Sports Medicine Vol. 20 (4) 2008: pp. 102-108