Physiological Approach to Cardio-endurance Training: Indicators of Optimal Parasympathetic Input on Cardiovascular Regulation are Better Predictors of Running Performance of Distance Runners

Poorly organized training schedules that are not focused on optimizing the cardiopulmonary fitness of the runner may lead to negative outcomes in their performance. Further, reduced cardiopulmonary fitness of a distance runner may lead to an imbalance of sympathetic and parasympathetic inputs of cardiac autonomic regulation. This altered balance of the regulation of the heart may recur as a vicious cycle, further hampering the runner's performance. The study assessed the effects of specialized training programs on the remodeling of cardiac autonomic regulation in relation to improving cardiopulmonary fitness and running performance of Sri Lankan male distance runners (N = 22). Before the intervention, runners were found to have more sympathetic dominancy on cardiac autonomic regulation along with suboptimal cardiopulmonary fitness level and suboptimal performance. After the intervention, more parasympathetic dominancy in cardiac autonomic regulation and improved cardiopulmonary fitness parameters were achieved. Post-intervention race timing of long-distance runners was significantly improved (p < 0.05) compared to the pre-intervention race timing irrespective of lower VO2peak level. The specialized training program used in this study optimized the parasympathetic dominancy of the autonomic regulation of the cardiovascular system of the Sri Lankan national long-distance runners. The runners were able to record significantly improved race timing after the specialized training intervention even though their VO2peak level was dropped. Thus, it is concluded that achieving parasympathetic dominant cardiac autonomic regulation is a better indicator than achieving higher VO2max levels given the performance of distance runners.