title: Prolonged expiration down to residual volume leads to severe arterial hypoxemia in athletes during submaximal exercise.
abstract: The goal of this study was to assess the effects of a prolonged expiration (PE) carried out down to the residual volume (RV) during a submaximal exercise and consider whether it would be worth including this respiratory technique in a training programme to evaluate its effects on performance. Ten male triathletes performed a 5-min exercise at 70% of maximal oxygen consumption in normal breathing (NB(70)) and in PE (PE(70)) down to RV. Cardiorespiratory parameters were measured continuously and an arterialized blood sampling at the earlobe was performed in the last 15s of exercise. Oxygen consumption, cardiac frequency, end-tidal and arterial carbon dioxide pressure, alveolar-arterial difference for O(2) (PA(O2) - Pa(O2)) and P(50) were significantly higher, and arterial oxygen saturation (87.4+/-3.4% versus 95.0+/-0.9%, p<0.001), alveolar (PA(O2)) or arterial oxygen pressure, pH and ventilatory equivalent were significantly lower in PE(70) than NB(70). There was no difference in blood lactate between exercise modalities. These results demonstrate that during submaximal exercise, a prolonged expiration down to RV can lead to a severe hypoxemia caused by a PA(O2) decrement (r=0.56; p<0.05), a widened PA(O2) - Pa(O2) (r=-0.85; p<0.001) and a right shift of the oxygen dissociation curve (r=-0.73; p<0.001).
authors: Université Paris 13, Laboratoire Réponses cellulaires et fonctionnelles à l'hypoxie, EA2363, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France. xwoorons@laposte.net
authors: Xavier
authors: X
authors: Woorons
authors: Pascal
authors: P
authors: Mollard
authors: Aurélien
authors: A
authors: Pichon
authors: Alain
authors: A
authors: Duvallet
authors: Jean-Paul
authors: JP
authors: Richalet
authors: Christine
authors: C
authors: Lamberto
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D045853:Exhalation / Q000502:physiology*; D005541:Forced Expiratory Volume; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008176:Lung Volume Measurements; D010100:Oxygen / Q000097:blood; D013177:Sports; D014797:Vital Capacity
chemical_list: D010100:Oxygen