Autonomic Responses to an Acute Bout of High-Intensity Body Weight Resistance Exercise vs. Treadmill Running
The aim of this study was to compare post-exercise autonomic nervous system (ANS) recovery between High-Intensity Training Protocol (HITP) and high-intensity treadmill running (TM) in ten physically fit males. For each trial ANS activity was measured though the Heart Rate Variability (HRV) markers of log-transformed square root of the successive R-R differences (lnRMSSD) and high frequency power (lnHF). These markers were analyzed in 5-min segments at 5-10 min pre-exercise period (PRE), and during the post-exercise period at 15-20min (POST15-20min), 20-25min (POST20-25min), 25-30min (POST25-30min), and 1hour (POST60min). Plasma epinephrine (E) and norepinephrine (NE) were also examined at PRE, immediately post exercise (IPE), 1-hour post (1HP), and 2-hour post (2HP). The results of this study demonstrate a significant overall time-dependent decreases in lnRMSSD and lnHF (p= 0.003) (p= 0.001) respectively in both trials. Trial-dependent differences were also observed in post-exercise lnRMSSD and lnHF measures, HITP being significantly lower than TM (p= 0.002)(p= 0.000). lnRMSSD at POST60min-HITP remained significantly lower compared to PRE (p < 0.05). lnHF returned to baseline in HIPT and TM (p= 0.081)(p= 0.065). A time dependent increase in E and NE was observed in both trials at time point IPE when compared to PRE (p < 0.05). E at 1HP and 2HP returned to near resting levels (p=0.62, p=0.26), while NE remained slightly elevated in both groups (p=0.003, p=0.021). A trial dependent increase was observed with HITP eliciting a greater E response (p=0.025) and NE response (p= 0.03). HITP causes a greater disruption of the ANS than intensity matched TM exercise.