Comparison of Heart Rate Variability Responses to Varying Resistance Exercise Volume-Loads

ABSTRACT

Purpose: The aim of this study was to compare the effects of low ([LV]; 4 total sets), moderate ([MV]; 8 total sets), and high set volumes ([HV]; 12 total sets) in acute full-body resistance exercise sessions on post-exercise parasympathetic reactivation measured using RMSSD. Methods: Ten resistance-trained participants (25.8 ± 6.8 yr., 173.4 ± 10.6 cm, 75.4 ± 9.9 kg) performed three resistance exercise sessions. During each session, heart rate variability (HRV) was measured pre- and for 30 min post-exercise, divided into 5-min segments stabilization, Post_5-10, Post_10-15, Post_15-20, Post_20-25, and Post_25-30. Repeated-measures ANOVA was used to assess differences within and between pre-post exercise natural logarithm RMSSD (LnRMSSD) values. To assess the initial change in LnRMSSD, the delta percent change (ΔLnRMSSD) from pre-exercise to Post_5-10 (ΔLnRMSSD_pre-post) was calculated for each session. The ΔLnRMSSD was also calculated between Post_5-10 and Post_25-30 (ΔLnRMSSD_post5-30) to assess recovery. Results: Significant differences were observed between sessions and when comparing pre-exercise values to all post-exercise times across sessions (p ≤ .05). The LV session resulted in significantly higher mean LnRMSSD value (3.62) post-exercise compared to both the MV (3.11, effect size [ES] =  3.77) and HV (3.02, ES =  3.92) sessions while the MV and HV sessions produced similar responses. Across sessions no return to baseline occurred and when comparing sessions, no significant differences were found in ΔLnRMSSD_pre-post or ΔLnRMSSD_post5-30. Conclusion: Acute bouts of full-body resistance exercise can cause similar reductions in LnRMSSD from pre-exercise levels and can delay parasympathetic reactivation back to baseline values during the same 30-min recovery period despite differences in set volume.

KEYWORDS:

• Autonomic modulation
• fatigue
• parasympathetic reactivation
• recovery
• weightlifting

Acknowledgments

The authors declare that the results of this study were presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. There were no conflicts of interest.

Additional information

Funding

This work was supported by the University of Alabama Graduate School for Student Research/Conference Travel funding.