Systolic Pressure Post‐Maximal Exercise is Associated with Arterial Stiffness and Baroreflex Sensitivity

Background Arterial stiffness is associated with cardiac dysfunction and coronary artery disease. The changes of stiffness post‐exercise is dependent on exercise intensity. Low intensity decreases stiffness while supramaximal exercise increases stiffness. The reason for the increase in stiffening occurring post‐maximal exercise is not well understood and may be due to central and peripheral stiffening or baroreflex resetting from maximal exercise. Purpose This project tested the hypothesis that the acute increase in blood pressure post‐maximal aerobic exercise is due to central and peripheral arterial stiffness and changes in baroreflex sensitivity (indexed as Δ heart rate /Δ blood pressure). Methods Eight healthy active (7057±2910 steps/day) subjects (6M/2F, 25±6y, 74±17kg) completed a treadmill maximal aerobic exercise test (56.6±12.4mL·kg·min) and a time control standing condition in random order separated by at least 7 days. Heart rate (HR), peripheral blood pressure (SYS, DIA, MAP) stiffness (augmentation index; AIX, pulse wave velocity; PWV) and total vascular conductance (TVC), and central blood pressures (cSYS, cDIA) were measured at 30, 60, 90‐ and 120‐minutes post‐exercise in supine position and baroreflex sensitivity was examined at post‐30 minutes. A 2‐way repeated measures analysis of variance was used to examine interaction and main effects for condition x time. Pearson correlations determined relationships between blood pressures and stiffness measures, exercise capacity and physical activity. Results The change (Δ) after maximal exercise compared to time control rest for HR (Δ13±15bpm), SYS (Δ4±9mmHg), MAP (Δ5±6mmHg), cSYS (Δ4±8mmHg) and PWV (Δ0.19±0.33cm/s) was greater from 30–120 min post‐maximal exercise (condition main effect, P≤0.03). Maximal aerobic exercise did not affect DIA, AIX, or TVC. Cardiac baroreflex sensitivity was increased to a greater extent after exercise (time control: 0.2±0.4 vs maximal exercise: 4.0±5.0 bpm/mmHg; P=0.02) and the ΔcSYS was strongly associated with the Δ arterial stiffness (PWV) accounting for 76% of the variance (P=0.0001). Conclusion These data indicate that maximal aerobic exercise increases systemic and central systolic blood pressure that is associated with an increased stiffening that may reflect the resetting of cardiac baroreflex sensitivity acutely after maximal aerobic exercise. Further understanding of these mechanisms underlying changes in PWV following maximal exercise may be physiologically relevant to cardiac loading and examining an appropriate baroreflex response that could be impaired in disease states that requires further study. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .