Experimental dyspnea as a stressor: differential cardiovegetative responses to inspiratory threshold loading in healthy men and women

Marie Cécile Niérat, Louis Laviolette, Anna Hudson, Thomas Similowski, Caroline Sévoz-Couche

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Niérat MC, Laviolette L, Hudson A, Similowski T, Sévoz-Couche C. Experimental dyspnea as a stressor: differential cardiovegetative responses to inspiratory threshold loading in healthy men and women. J Appl Physiol 123: 205–212, 2017. First published May 4, 2017; doi:10.1152/japplphysiol.00078.2017.—Dyspnea is associated with an emotional reaction that involves limbic activation. The inspiratory threshold load (ITL) is known to elicit a dyspneic response in healthy subjects. Laboratory-induced stress conditions have been shown to elicit sex-related differences in cardiovascular responses. The aim of this study was to evaluate how healthy men (n = 8) and women (n = 9) react and adapt to 5-min periods of ITL at three levels (low, medium, and high) in terms of heart rate (HR), temporal (RMSSD) and spectral (LF, HF, LF/HF ratio) HRV indexes, and rating of breathing discomfort. HR increased with low, medium, and high ITL in men, whereas it increased only with high ITL in women. LF/HF ratio increased at low ITL in both men and women. Modifications appear to depend essentially on increased LF in men and on reduced HF in women. In addition, HRV modifications differ between men and women, following the order of presentation of ITLs. Our results show a continuous and sustained stress in men (increased HR, LF, and LF/HF ratio across ITL presentation) and a stress adaptation in women. Subjective responses of breathing discomfort were not correlated with sympatho-vagal balance modifications for a subgroup of subjects (n = 10). Breathing against the ITL induced autonomic modifications that are different between men and women, i.e., driven by sympathetic mediated responses in men, whereas women showed a greater parasympathetic modulation of cardiovascular activity. These results highlight the role of the mechanical inspiratory load in the heart rate variability seen in chronic obstructive pulmonary disease. 

NEW & NOTEWORTHY Breathing against the ITL induced autonomic modifications driven by sympathetic mediated responses in men, whereas women showed a greater parasympathetic modulation of cardiovascular activity, even for low load. A stress circuit could be at the origin of autonomic modifications induced by ITL. Our results would underline the role of the mechanic inspiratory load in the abnormalities in heart rate variability seen in COPD patients.

Original languageEnglish
Pages (from-to)205-212
Number of pages8
JournalJournal of Applied Physiology
Volume123
Issue number1
DOIs
Publication statusPublished - Jul 2017
Externally publishedYes

Keywords

  • dyspnea
  • gender differences
  • healthy subjects
  • ITL
  • short-term HRV
  • stress

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