Exercise breathing pattern during chronic altitude exposure

I. B. Mekjavic, C. Moric, S. V. Goldberg, J. B. Morrison, M. L. Walsh, E. W. Banister, R. B. Schoene

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Breathing pattern in response to maximal exercise was examined in four subjects during a 7-day acclimatisation to a simulated altitude of 4247 m (barometric pressure, PB = 59.5 kPa). Graded exercise tests to exhaustion were performed during normoxia (day 0), and on days 2 and 7 of hypoxia, respectively. Ventilation was significantly augmented in the hypoxic environment, as were both the mean inspiratory flow (VT/TI) and inspiratory duty cycle (TI/TTOT) components of it. VI/TI was increased due to a significant increase in tidal volume (VT) and a corresponding decrease in inspiratory time duration (TI). Throughout a range of exercise ventilation, TI/TTOT was increased due to an apparently greater decrease in expiratory time duration (TE) with respect to TI. In all cases, the relation between VT and TI displayed a typical range 2 behaviour, with evidence of a range 3 occurring at very high ventilatory rates. There was essentially no difference observed in the VT-TI relation during exercise between the normoxic and hypoxic conditions. No significant changes were observed in the breathing pattern in response to exercise within the exposure period (from day 2 to day 7), although there was a discernible tendency to a higher stage 3 plateau by day 7 of altitude exposure.

Original languageEnglish (US)
Pages (from-to)61-65
Number of pages5
JournalEuropean Journal of Applied Physiology and Occupational Physiology
Issue number1
StatePublished - Jan 1 1991
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physiology
  • Public Health, Environmental and Occupational Health


  • Graded exercise
  • Hypobaric hypoxia
  • Mean inspiratory flow
  • Regulation of breathing
  • Respiratory phase durations

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