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

doi:10.1007/bf00635636

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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

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Abstract

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.

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Acclimatization Adult Altitude Breathing Exercises Exercise Humans Hypoxia Male Respiration Time Factors Journal Article Research Support, Non-U.S. Gov't

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I B Mekjavic, C Moric, S V Goldberg, J B Morrison, M L Walsh, E W Banister, R B Schoene. 1991. Exercise breathing pattern during chronic altitude exposure.. https://doi.org/10.1007/bf00635636

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