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Moderate exercise in hypoxia induces a greater arterial desaturation in trained than untrained men
Author(s) -
Woorons X.,
Mollard P.,
Pichon A.,
Lamberto C.,
Duvallet A.,
Richalet J.P.
Publication year - 2007
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2006.00577.x
Subject(s) - hypoxia (environmental) , ventilatory threshold , pulse oximetry , medicine , cardiology , anesthesia , heart rate , blood pressure , oxygen , vo2 max , chemistry , organic chemistry
During moderate exercise breathing a low inspired O 2 fraction ( F I O 2 ), arterial O 2 desaturation may depend on the fitness level. Seven trained (TM) and seven untrained men (UTM) cycled in normoxia and in hypoxia ( F I O 2 =0.187, 0.173, 0.154, 0.13 and 0.117). We compared TM and UTM at submaximal intensities below the ventilatory threshold. Ventilatory variables were monitored and arterial oxygen saturation was measured by pulse oximetry. O 2 saturation was not different between groups at sea level. In hypoxia, O 2 saturation was lower in TM than in UTM at F I O 2 =0.154 (87.3 ± 2.9% vs 90.4 ± 1.5% at 90 W) and below. Both the ventilatory‐equivalent and the end‐tidal O 2 pressure were lower in TM at sea level and at every F I O 2 , with the differences between TM and UTM becoming apparent at lower exercise intensity and increasing in magnitude as the severity of hypoxia increased. O 2 saturation was correlated with the ventilatory parameters at every F I O 2 and the correlations were stronger in severe hypoxia. These results demonstrate that a moderate exercise carried out in hypoxia, contrary to normoxic conditions, can lead to a greater arterial desaturation in TM compared with UTM. This phenomenon could be partly attributed to a relative hypoventilation in trained subjects.