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. 2025 Jun 30:16:1579929.
doi: 10.3389/fphys.2025.1579929. eCollection 2025.

Effects of different incremental treadmill exercise protocols on the autonomic nervous system in healthy college students: a comparative study based on heart rate variability analysis

Yingying Cao #  1   2 , Shuairan Li #  3 , Yi Zha  1 , Xin Yan  1 , Jingdong Jia  1 , Yuanyuan Luo  4 , Aiping Chi  2
Affiliations

Effects of different incremental treadmill exercise protocols on the autonomic nervous system in healthy college students: a comparative study based on heart rate variability analysis

Yingying Cao et al. Front Physiol. .

Abstract

Objectives: This study aimed to examine the acute regulatory effects of three different incremental load treadmill exercise protocols on autonomic nervous system (ANS) function in healthy college students. The ultimate goal was to inform evidence-based training strategies and enhance cardiopulmonary function assessment in this population.

Methods: Forty healthy male college students were recruited to complete three incremental treadmill protocols: Ellestad A, Ellestad B, and Bruce. Participants were equipped with an energy expenditure monitor (GT9-X, ActiLife 1.0), and heart rate (HR) and heart rate variability (HRV) data were recorded at three time points: pre-exercise, immediately post-exercise, and 5 minutes post-exercise. HRV was analyzed using time-domain indices (SDNN, RMSSD, PNN50), frequency-domain indices (LF, HF), and nonlinear metrics derived from Poincaré plots (SD1, SD2), in order to evaluate the impact of exercise intensity on autonomic regulation.

Results: All three protocols resulted in significant reductions in time-domain, frequency-domain, and nonlinear HRV indices compared to pre-exercise baseline values (p < 0.01), indicating marked autonomic suppression. Compared to the immediate post-exercise period, HRV continued to decline following the Ellestad A and B protocols (p < 0.01), while a significant rebound was observed after the Bruce protocol (p < 0.01). Furthermore, the LF/HF ratio progressively increased across the three protocols, revealing a significant main effect of exercise intensity (p < 0.01).

Conclusion: (1) All three incremental treadmill protocols elicited acute HRV alterations, characterized by parasympathetic withdrawal and sympathetic activation, reflecting a transient state of autonomic imbalance; (2) HRV serves as a sensitive physiological marker for detecting exercise-induced fatigue and quantifying training load intensity. Under the Ellestad A and B protocols, heart rate variability (HRV) exhibited a sustained decline throughout the 5-min recovery period, potentially indicating that exercise-induced fatigue load may not have been fully resolved. However, this interpretation warrants further validation through additional objective physiological markers. While the rebound observed after the Bruce protocol may suggest acute autonomic recovery associated with supercompensation and adaptive responses to high-intensity exercise.

Keywords: HRV; Poincaré scatter plot; incremental load; sport intensity; treadmill exercise regimes.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
Poincaré scatter plot of lower healthy college students under incremental load model.
FIGURE 2
FIGURE 2
Exercise load assessment of healthy college students under three running platform models. Note: (a: physiological load index; b: RPE; c: HRR%; d: %HRmax) **, p < 0.01 compared with Ellestad B; ##, p < 0.01 compared with Ellestad A.
FIGURE 3
FIGURE 3
Experimental procedure.
FIGURE 4
FIGURE 4
Comparative results of SD1 and SD2 indicators of students under the incremental load model. Note: **, compared with Ellestad A (p < 0.01); △△, compared with Ellestad B (p < 0.01).
FIGURE 5
FIGURE 5
Heart rate result.
See this image and copyright information in PMC

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References

    1. Aguinis H., Gottfredson R. K., Culpepper S. A. (2013). Best-practice recommendations for estimating cross-level interaction effects using multilevel modeling. J. Manag. 39 (6), 1490–1528. 10.1177/0149206313478188 - DOI
    1. Ainsworth B. E., Haskell W. L., Herrmann S. D., Meckes N., Bassett Jr D. R., Tudor-Locke C., et al. (2011). 2011 Compendium of Physical Activities: a second update of codes and MET values. Med. and Sci. Sports and Exerc. 43 (8), 1575–1581. 10.1249/MSS.0b013e31821ece12 - DOI - PubMed
    1. Blanca M. J., Arnau J., García-Castro F. J., Alarcón R., Bono R. (2023). Repeated measures ANOVA and adjusted F-tests when sphericity is violated: which procedure is best? Front. Psychol. 14, 1192453. 10.3389/fpsyg.2023.1192453 - DOI - PMC - PubMed
    1. Borg G. A. (1982). Psychophysical bases of perceived exertion. Med. Sci. sports Exerc. 14 (5), 377–381. 10.1249/00005768-198205000-00012 - DOI - PubMed
    1. Brysbaert M. (2019). How many participants do we have to include in properly powered experiments? A tutorial of power analysis with reference tables. J. cognition 2 (1), 16. 10.5334/joc.72 - DOI - PMC - PubMed

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