Hypertensive responses to exercise after 12-weeks of high-intensity interval training or moderate-to-vigorous intensity continuous training in patients with persistent and permanent atrial fibrillation: a non-prespecified post-hoc analysis of a randomized clinical trial

OBJECTIVES: Does 12-weeks of high-intensity interval training or moderate-to-vigorous intensity continuous training lead to changes in hypertensive responses to exercise in adults with atrial fibrillation? DESIGN: Non-prespecified post-hoc analysis of a randomized clinical trial. METHODS: Participants were randomised to a 12-week, twice weekly intervention of high-intensity interval training (2 × 8-minute blocks with 30 s high-intensity intervals at 80-100% peak power output interspersed with 30-seconds active recovery) or moderate-to-vigorous intensity continuous training (60 minutes of continuous aerobic training at 67-95% heart rate peak). To examine hypertensive responses to exercise, blood pressure was taken immediately following a six-minute walk test at baseline and follow-up. RESULTS: Eighty-six participants were randomized to high-intensity interval training (n = 43, age: 68 (8) years, 33% female) or moderate-to-vigorous intensity continuous training (n = 43, age: 71 (7) years, 33% female). A higher proportion of moderate-to-vigorous intensity continuous training participants had clinically meaningful reductions in peak systolic blood pressure (Δ=-10mmHg or more) than high-intensity interval training (43% vs 19%, p = 0.029). A trend for a small reduction in hypertensive responses to exercise relative to fitness after aerobic training, with 55% of the cohort experiencing a reduction (baseline: 42 ± 8 mmHg/METs; follow-up: 41 + 14 mmHg/METs; p = 0.0501). Within-sex analyses showed that a higher proportion of females had clinically meaningful reductions in peak systolic blood pressure following moderate-to-vigorous intensity continuous training than high-intensity interval training (43% vs 7%). CONCLUSIONS: Both high-intensity interval training and moderate-to-vigorous intensity continuous training may reduce hypertensive responses to exercise in adults with atrial fibrillation. No sex differences were observed.