Effects of high-intensity interval training and moderate-intensity continuous training on the functioning of attentional networks and heart rate variability in healthy young adults.

Objective: Human attentional mechanisms comprise three distinct networks: alerting, orienting, and executive control. Studies assessing the acute effects of moderate-intensity continuous training (MICT) on these networks have yielded inconsistent results. Similarly, the acute effects of high-intensity interval training (HIIT) on these networks remain unclear. Therefore, this study investigated the effects of HIIT and MICT on the functioning of attentional networks and explored the relationship between heart rate variability (HRV) and these networks in healthy young adults. Methods: Thirty-six healthy college students completed HIIT, MICT, and a resting (CON) session in a randomized cross-over design. The HIIT protocol comprised 10 × 1-min bouts at 100 % peak power output (Wpeak) with 1 min of active recovery at 20 % Wpeak. The MICT protocol was applied at 40 % Wpeak for 30 min. Functioning of the attentional networks was assessed post-intervention using the Attention Network Test for Interactions (ANT-I). HRV was recorded pre- and post-exercise/rest and during the ANT-I. Results: HIIT significantly reduced the alerting function compared to CON ( Conclusion: A single session of HIIT selectively modulated the functioning of attentional networks, decreasing alerting function while enhancing executive control. These effects were partly mediated by increased arousal resulting from parasympathetic withdrawal.