Task-related attentional processes are distinctly modulated by respiration and RR interval variability

Changes in reaction times (RTs) during attentional processing may be associated with the state of breathing. Although breathing and cardiac activity interact, the functional importance of the cardiorespiratory system for modulating attentional processing remains unclear. To determine the involvement of respiration and RR interval (RRI) variability in successful task performance, thirty-six healthy participants performed a short-term memory task. For RTs limited to correct responses, increases were observed under two conditions: i) when inspiratory onset (or exhalation-to-inhalation transition) occurred and ii) when RRI velocity increased during retrieval. Importantly, multilevel model analysis revealed that the timing of inspiratory onset and the increase in RRI velocity were temporally mismatched, suggesting that at least two independent mechanisms may prolong RT. These findings contribute to a better understanding of how respiration and RRI variability may be functionally differentiated and how each could be linked to attentional processes that influence performance.