Home-based Exercise Training When You Can't Leave The House: Promoting Physical Activity In Postpartum Women

PURPOSE: To establish feasibility of a high intensity interval training (HIIT) intervention administered at home remotely in insufficiently active postpartum women (PW), and to test the hypothesis that the volume of exercise completed will improve select physiological and psychological outcomes. METHODS: 13 PW were randomized to a 6-week, 4 days/week HIIT program (E) or usual care (U). E sessions included 8-15-minutes of HIIT (20/40 sec @ HR 85% of estimated peak heart rate (HRpeak)) on a stepper machine. HR was recorded continuously, producing an HR curve and exercise volume was computed as the sum (AUCsum) area under these HR curves. Estimated VO2max, heart rate recovery (HRR), anthropometrics, blood pressure (BP), mood and readiness to exercise questionnaires, inflammatory markers, and 24-hour ECG were collected pre and posttest. Mann-Whitney U tests were used to test for differences in the change scores pre and post intervention. Spearman’s Rho were calculated between changes in VO2max and AUCsum and the study outcomes. RESULTS: E participants completed 80.2 ± 27% of the 24 sessions and adherence to the prescribed HIIT regimen was 73.4 ± 33%. VO2max not significantly improved in E and decreased in U (E: +2.29 (.23, 10); U: -1.35 (-6.41, 2.7) ml·kg-1·min-1). There were no group differences in the distribution of the change scores of the physiological outcomes with the exception of HRR at 120 seconds. Both HRR at 60 and 120 seconds improved in the E compared to the U group but only the latter reached significance level (p = .048). There were no group differences in the psychological outcomes. The E experienced nonsignificant decreases in negative affect compared to an increase in the U. AUCsum and change in VO2peak were not significantly associated with changes in any of the psychological outcomes. AUCsum was inversely correlated with changes in systolic BP (r = - .717, p = .003), IL-1β (r = -.70, p = .036) and HMGB1 (r = -.72, p = .03). CONCLUSIONS: We have demonstrated the feasibility of an entirely home-based exercise intervention in PW with limited ability to leave home. We were unable to detect substantive improvements in the study outcomes in this underpowered pilot study. AUCsum was significantly correlated with improvements in some physiological outcomes that have significant prognostic value for the health of the new mother.