The Relationship Between the Cortico‐Diaphragmatic Conduction Pathway and Cardiopulmonary Function in Healthy Individuals

ABSTRACT Aims To investigate whether there is a correlation between the parameters of cardiopulmonary function tests and corticospinal diaphragm pathway parameters in healthy individuals. Methods Seventeen healthy adults participated in all tests. Transcranial magnetic stimulation (TMS) was employed to assess corticospinal diaphragm excitability, measuring the diaphragmatic resting motor threshold (DRMT), cortical motor evoked potential amplitude (CMEPA), and cortical motor evoked potential latency (CMEPL). Functional capacity was evaluated using the 6‐min walk test (6MWT), pulmonary ventilation function was assessed via pulmonary function tests (PFT), and cardiopulmonary endurance was determined by cardiopulmonary exercise test. (CPET). The relationships between TMS‐derived parameters and cardiopulmonary function indices were examined using correlation analysis and stepwise regression analysis. Results Regression analyses identified two key independent predictors. First, forced expiratory volume in 1 s (FEV1) was an independent predictor of DRMT. DRMT also correlated with other measures of pulmonary function and exercise capacity. Second, maximum heart rate (HR max ) was an independent predictor of CMEPL. CMEPL also showed positive correlations with other cardiopulmonary parameters. Conclusion This study demonstrates that in healthy adults, better pulmonary function (reflected by higher FEV1) is associated with a higher DRMT and greater cardiovascular reserve (reflected by higher HR max ) is associated with longer CMEPL. These novel associations suggest a link between routine cardiopulmonary metrics and the central neural control of breathing, warranting further investigation.