Association Between cnm-Positive Streptococci and Cerebral Small Vessel Disease: Insights From Oral Health and Microbiome Status.

The pathophysiology of exercise intolerance of heart failure with preserved ejection fraction (HFpEF) is complex and involves multiple physiologic systems (, ). In this context, patients with HFpEF have respiratory muscle dysfunction that includes inspiratory muscle weakness and reduced inspiratory muscle fatigue resistance (, ). Inspiratory muscle weakness is associated with higher mortality, reduced functional capacity, and more severe exertional dyspnea in patients with HFpEF (–). During submaximal exercise, patients with HFpEF have limited ventilatory reserve, abnormal breathing pattern response, and higher work and cost of breathing than controls (–). High inspiratory work and concomitant metabolite accumulation are associated with neural and cardiovascular consequences. In this context, high inspiratory work in healthy adults at rest elicits time-dependent increases in sympathetic outflow, mean arterial pressure (MAP), and limb vascular resistance, decreasing leg blood flow (–) via the inspiratory muscle metaboreflex. High inspiratory muscle work during exercise has important implications for exercise tolerance and locomotor muscle oxygen delivery (). We recently found that patients with HFpEF have abnormal inspiratory muscle metaboreflex mediated cardiovascular responses (). Specifically, high inspiratory work was associated with greater increases in MAP and leg vascular resistance as well as decreases in leg blood flow in patients with HFpEF compared to controls (). Inspiratory muscle training (IMT) specifically targets the respiratory muscles and improves inspiratory muscle strength (). In patients with HFpEF, IMT is associated with increases in maximal inspiratory pressure (MIP), functional capacity, and quality of life (), but the effect of IMT on the inspiratory muscle metaboreflex mediated cardiovascular responses in patients with HFpEF is unclear. Accordingly, the purpose of this study was to investigate the impact of IMT on cardiovascular responses during high-intensity inspiratory loading in patients with HFpEF. We hypothesized that IMT will attenuate the 1) increases in MAP and leg vascular resistance as well as 2) decrease in leg blood flow during high-intensity inspiratory loading in patients with HFpEF.