Impact of high-intensity interval and moderate-intensity continuous exercise on heart rate variability and cardiac troponin

BACKGROUND: It remains uncertain whether exercise modality (high-intensity interval [HIE]; moderate-intensity continuous [MCE]) mediates exercise-induced changes in markers of pro-arrhythmogenic state and/or cardiac damage. This study examines heart rate variability (HRV) and troponin T (cTnT) kinetic responses to HIE MCE.METHODS: Fourteen sedentary, overweight/obese females completed two trials including (2-min running at 90% V?O2max followed by 2-min 50% V?O2max, repeated for 60 min) MCE (70% steady-state a randomized, counterbalanced fashion. Supine HRV was evaluated as root mean square successive differences (RMSSD), normalized low-frequency (LF) high-frequency (HF) spectral power, well the LF/HF ratio before (PRE), immediately (0 HR), 3 (3 HR) 24 (24 hours after exercise. Serum cTnT assessed using high-sensitivity assay same time-points values were corrected plasma volume changes.RESULTS: Exercise temporarily altered all indices (i.e. RMSSD HF decreased; LF increased 0 HR, P<0.05) but rebound increase observed similar between modalities. The significantly elevated (P<0.05) HR (by 688%) 374%) with no between-modality differences. There significant correlation delta change metrics.CONCLUSIONS: (workload-equivalent vs. MCE) did not mediate alteration autonomic activity elevation, it seems these are largely separate phenomena.