The pattern of breathing during hypoxic exercise
1987 (English)In: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, Vol. 56, no 6, 619-622 p.Article in journal (Refereed) Published
Breathing pattern was studied in six subjects in normoxia (FIO2 = 0.21) and hypoxia (FIO2 = 0.12) at rest and during incremental work-rate exercise. Ventilation (V) as well as mean inspiratory flow (VT/TI) increased with exercise intensity and were augmented in the hypoxic environment, whereas the ratio between inspiratory (TI) and total (Ttot) breath durations increased with exercise intensity but was unaffected by hypoxia. The relationship of tidal volume (VT) and inspiratory time duration (TI) showed linear, coinciding ranges for the normoxic and hypoxic conditions up to VT/TI values of about 2.5 1.s-1. At higher VT/TI values TI continued to decrease, whereas VT tended to level off, an effect which was more evident in the hypoxic condition. The results suggest that the hypoxic augmentation of exercise hyperpnea is primarily brought about by an enhancement of central inspiratory drive, the timing component being largely unaffected by the hypoxic environment, and that at low to moderate levels of exercise hyperpnea inspiratory off-switch mechanisms are essentially unaffected by moderate hypoxia.
Place, publisher, year, edition, pages
1987. Vol. 56, no 6, 619-622 p.
Control of respiration, Hypoxia, Graded exercise, Mean inspiratory flow, Respiratory phase durations, Volume threshold curves
IdentifiersURN: urn:nbn:se:kth:diva-44639DOI: 10.1007/BF00424799ISI: A1987K106400001PubMedID: 3678212OAI: oai:DiVA.org:kth-44639DiVA: diva2:452183
QC 201111172011-10-282011-10-252011-11-17Bibliographically approved