Effect of limb muscle fatigue on perception of respiratory effort in healthy subjects

Antonello Grippo, Riccardo Carrai, Linda Chiti, Giulia Innocenti Bruni, Giorgio Scano, Roberto Duranti

Research output: Contribution to journalArticle

Abstract

The role of nonrespiratory peripheral afferents in dyspnea perception has not been fully elucidated yet. Our hypothesis is that fatigue-induced activation of limb muscle metaboreceptors served by group IV fine afferent fibers may impact on respiratory effort perception. We studied 12 healthy subjects breathing against progressive inspiratory resistive loads (10, 18, 30, 40, and 90 cmH2O·l-1·s) before and after inducing low-frequency fatigue of quadriceps muscle by repeating sustained contractions at ≥80% of maximal voluntary contraction. Subjects also underwent a sham protocol while performing two loaded breathing runs without muscle fatigue in between. During the loaded breathing, while subjects mimicked the quiet breathing pattern using a visual feedback, ventilation, tidal volume, respiratory frequency, pleural pressure swings, arterial oxygen saturation, end-tidal partial pressure of CO2, and dyspnea by a Borg scale were recorded. Compared with prefatigue, limb muscle fatigue resulted in a higher increase in respiratory effort perception for any given ventilation, tidal volume, respiratory frequency, pleural pressure swings, end-tidal partial pressure of CO2, and arterial oxygen saturation. No difference between the two runs was observed with the sham protocol. The present data support the hypothesis that fatigue of limb muscles increases respiratory effort perception associated with loaded breathing, likely by the activation of limb muscle metaboreceptors.

Original languageEnglish
Pages (from-to)367-376
Number of pages10
JournalJournal of Applied Physiology
Volume109
Issue number2
DOIs
Publication statusPublished - Aug 2010

Keywords

  • Metaboreceptors
  • Peripheral muscle afferents
  • Resistive breathing

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Medicine(all)

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