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cardiac auto-regulation, frequency domain, time domain, blood pressure, exercise


Physically inactive adults are prevalent worldwide. This study compared the effects of short-term high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on heart rate variability (HRV) in physically inactive adults as a preliminary study. Thirteen physically inactive male adults (27.5 ± 3.80 years) were randomly assigned to HIIT (N = 7) or MICT (N = 6). The HIIT program consisted of 20 min of interval training with cycling to rest ratio of 10/50 s at ≥90% HRpeak, while the MICT program consisted of 40 min of continuous cycling at 60–75% HRpeak. Both groups completed eight sessions of training within two weeks. Time and frequency domains of HRV were measured for 20 min with Actiwave-Cardio monitor (CamNtech, UK). The number of R-R interval and inter-beat interval (IBI) were significantly improved (p < 0.05) in both HIIT and MICT programs following eight sessions of training. A significant interaction effect for group by time was found in the lnLF/HF ratio (p < 0.05) where it was only improved in the HIIT group from pre- to post-test. The HIIT program is superior to MICT in improving HRV in physically inactive adults. The HIIT program can be applied as a time-efficient program for improving cardiac-autoregulation.

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This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Alansare, A.; Alford, K.; Lee, S.; Church, T.; Jung, H.C. The Effects of High-Intensity Interval Training vs. Moderate-Intensity Continuous Training on Heart Rate Variability in Physically Inactive Adults. Int. J. Environ. Res. Public Health 2018, 15, 1508.