Daily Paced Breathing Sessions Induce Left Orbitofrontal Volume Changes Linked to Cognitive Outcomes

Oscillatory coupling between respiration, heart rate, and cortical function is fundamental to physiological regulation yet remains poorly characterized in humans. Diminished respiratory heart rate variability (RespHRV)--the rhythmic heart rate modulation accompanying respiration--has emerged as a transdiagnostic biomarker of mental and physical health, reduced in anxiety, depression, cardiovascular disease, and aging (Beauchaine & Thayer, 2015; Menuet & Gourine et al., 2025). However, the cortical substrates that coordinate rhythmic cardiovascular-respiratory coupling are not well understood. Our current findings highlight the involvement of the left orbitofrontal cortex (OFC) in oscillatory cardiorespiratory dynamics. In adults aged 50-70 (N = 55; mean age = 60.1 {+/-} 6.0 years; 29 female), across both a slow-paced breathing condition and a random-paced breathing condition, greater heart rate oscillatory power during 9-week breathing training sessions predicted OFC volume increases. OFC changes were most strongly linked with upper low-frequency range power during practice (0.09-0.13 Hz; p < 0.005, cluster-corrected) but were not tightly constrained by precise breathing frequency. These effects covaried with improved attentional and executive performance, including reduced pupil responses to distractors and enhanced working-memory and associative-memory scores. Our findings identify the orbitofrontal cortex as a key site of cortical plasticity linked to rhythmic cardiovascular-respiratory engagement. By delineating how oscillatory body-brain coupling supports cognitive control-related processes, including attentional filtering and memory updating, this work bridges mechanistic neuroscience and translational intervention science, suggesting a frequency-general pathway through which simple breathing practices may enhance neurovisceral integration and cognitive resilience in aging. SummaryO_LIGreater oscillatory heart rate power during breathing training, particularly within the upper low-frequency range (0.09-0.13 Hz), predicted increases in left orbitofrontal cortex (OFC) volume. C_LIO_LIOFC volume increases were associated with improved attentional and executive performance, including reduced pupil reactivity to distractors and enhanced working-memory and associative-memory scores. C_LIO_LIThese findings suggest that rhythmic cardiovascular-respiratory coupling supports cortical plasticity and cognitive resilience, providing a frequency-general mechanism through which breathing practices enhance neurovisceral integration in aging. C_LI