Recent research indicates that humans continuously and automatically modulate their breathing to temporally align exteroceptive stimuli with specific phases of the respiratory cycle. This process has been interpreted as a form of active sensing and is associated with faster responses and improved perceptual accuracy. While converging evidence suggests that respiration also shapes interoceptive processing at both neural and behavioural levels, it remains unclear whether individuals actively adjust their breathing to optimize interoceptive performance. In this study, we examined whether healthy participants modulated their respiration during an interoceptive (heartbeat discrimination) and an exteroceptive (tactile detection) task. We analysed respiration both in terms of time-locked activity and inter-trial phase coherence relative to stimulus onset and assessed their relationship with perceptual accuracy. Our results demonstrated that participants systematically adjust their breathing in both amplitude and phase, synchronizing respiration to the anticipated (i.e., cued) onset of stimuli in both tasks. Crucially, task performance was enhanced during exhalation compared to inhalation, suggesting that respiratory modulation supports the perception of both interoceptive and exteroceptive signals. Significance statement This study reveals that humans not only synchronize their breathing to anticipated external and internal stimuli, but also perform better when perceiving them during exhalation. By showing that respiration is modulated in both interoceptive and exteroceptive contexts, our findings extend the concept of active sensing to internal bodily awareness. This has important implications for understanding the dynamic interplay between physiology and perception and may guide interventions aimed at improving clinical outcomes in conditions where interoception is disrupted. ### Competing Interest Statement The authors have declared no competing interest. European Union’s HORIZON-WIDERA-2021-ACCESS-05-01- European Excellence Initiative, 101071321 European Union - NextGenerationEU, 1409/2022, 1016

The phasic cardiovascular activity influences the central nervous system through the systolic baroreceptor inputs, inducing widespread inhibitory effe…

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