Open AccessVentilatory oscillations at exercise: effects of hyperoxia, hypercapnia, and acetazolamide
Author(s) -
Hermand Eric,
Lhuissier François J.,
Larribaut Julie,
Pichon Aurélien,
Richalet JeanPaul
Publication year - 2015
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12446
Subject(s) - hypercapnia , hyperoxia , acetazolamide , medicine , hypoxia (environmental) , anesthesia , ventilation (architecture) , hypoventilation , placebo , periodic breathing , respiratory minute volume , cardiology , respiratory system , apnea , chemistry , acidosis , oxygen , lung , mechanical engineering , organic chemistry , engineering , alternative medicine , pathology
Periodic breathing has been found in patients with heart failure and sleep apneas, and in healthy subjects in hypoxia, during sleep and wakefulness, at rest and, recently, at exercise. To unravel the cardiorespiratory parameters liable to modulate the amplitude and period of ventilatory oscillations, 26 healthy subjects were tested under physiological (exercise) and environmental (hypoxia, hyperoxia, hyperoxic hypercapnia) stresses, and under acetazolamide ( ACZ ) treatment. A fast Fourier transform spectral analysis of breath‐by‐breath ventilation ( V ˙ E ) evidenced an increase inV ˙ E peak power under hypercapnia (vs. normoxia and hyperoxia, P < 0.001) and a decrease under ACZ (vs. placebo, P < 0.001), whereas it was not modified in hyperoxia.V ˙ E period was shortened by exercise in all conditions (vs. rest, P < 0.01) and by hypercapnia (vs. normoxia, P < 0.05) but remained unchanged under ACZ (vs. placebo).V ˙ E peak power was positively related to cardiac output ( Q ˙ c ) andV ˙ E in hyperoxia ( P < 0.01), in hypercapnia ( P < 0.001) and under ACZ ( P < 0.001).V ˙ E period was negatively related toQ ˙ c andV ˙ E in hyperoxia ( P < 0.01 and P < 0.001, respectively), in hypercapnia ( P < 0.05 and P < 0.01, respectively) and under ACZ ( P < 0.05 and P < 0.01, respectively). Total respiratory cycle time was the main factor responsible for changes inV ˙ E period. In conclusion, exercise, hypoxia, and hypercapnia increase ventilatory oscillations by increasingQ ˙ c andV ˙ E , whereas ACZ decreases ventilatory instability in part by a contrasting action on O 2 and CO 2 sensing. An intrinsic oscillator might modulate ventilation through a complex system where peripheral chemoreflex would play a key role.