Author/Editor		Mekjavić, IB; Moric, C; Goldberg, SV; Morrison, JB; Walsh, ML; Banister, EW; Schoene, RB
Title		Exercise breathing pattern during chronic altitude exposure
Type		članek
Source		Eur J Appl Physiol
Vol. and No.		Letnik 62, št. 1
Publication year		1991
Volume		str. 61-5
Language		eng
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.
Descriptors		ALTITUDE BREATHING EXERCISES RESPIRATION ACCLIMATIZATION ADULT ANOXIA EXERCISE TIME FACTORS