Abstract 19716: A High Intensity Interval Training Protocol is Not Better Than Customary Continuous Exercise for a Rat Model of Chronic Thromboembolic Pulmonary Hypertension

High intensity interval training (HIIT) is superior to continuous exercise training (CExT) for reversing cardiac remodeling and dysfunction and improving exercise capacity in heart failure. Our group recently observed greater HIIT benefit in a pulmonary arterial hypertension (PAH) rat model as well. Here we investigated HIIT vs. CExT for chronic thromboembolic pulmonary hypertension (CTEPH). Methods: Male SD rats (~375g) were injected with polystyrene microspheres (97/100g, 85μm, jugular vein) and SU 5416 (20mg/kg, sc.) to produce chronic pulmonary embolism (CPE, n=6), or vehicle (Sham, n=6). Subgroups of each (CPE+HIIT, Sham+HIIT, CPE+CExT, Sham+CExT, n=6 ea) underwent 6 wks (5x/wk) of treadmill running performed either as 30 min HIIT (5 x [2 min @ 85%VO2max + 3 min @ 30%VO2max) or 60 min mild CExT (50% VO2max). Sedentary counterparts were placed on a stationary treadmill (Sham+SED and CPE+SED, n=6 ea). Results: CPE+SED had lower (p<0.05) final VO2max (in ml/kg/hr) (2656±73) post-CPE,vs. Sham+SED (3576±1...