«¿El ejercicio induce hipoxemia arterial en triatletas dependiendo de la modalidad de ejercicio?»
O. Galy1, D. Le Gallais2, O. Hue1, A. Boussana2, C. Préfaut3
1 Laboratoire ACTES, UFR-STAPS Antilles-Guyane, Pointe à Pitre Cedex, France 2 Laboratoire Sport, Performance, Santé, UPRES-EA, UFR-STAPS, 700, Montpellier, France 3 UPRES EA 701, Laboratoire de Physiologie des Interactions, Service Central de Physiologie Clinique, Centre Hospitalier Universitaire Arnaud de Villeneuve, Montpellier Cedex 5, France
To determine whether exercise modality affects arterial hypoxemia (EIAH) during training-intensity exercise, 13 triathletes performed 20 min of cycling (C) followed by 20 min of running (R): C-R, and two weeks later, 20 min of R followed by 20 min of C: R-C. Each trial was performed at an intensity slightly above the ventilatory threshold and close to the daily training intensity (75 % of V·O2max). Ventilatory data were collected continuously using an automated breath-by-breath system. Partial pressure of oxygen in arterial blood (PaO2) was measured after each C and R segment and arterial oxyhemoglobin saturation (SpO2) was monitored continuously via pulse oximetry. The metabolic rate was similar across modalities and trials, i.e., C-R (53.8 ± 3.8 vs. 51.1 ± 5.3 ml · min-1 · kg-1) and R-C (52.2 ± 4.5 vs. 53.2 ± 4.6 ml · min-1 · kg-1). EIAH showed significantly greater severity for R compared to C irrespective of the order (p < 0.05 for both trials). R values of PaO2 (and SpO2) for C-R and R-C were 88.7 ± 6.0 mm Hg (93.0 ± 0.6 % SpO2) and 86.6 ± 7.3 mm Hg (93.5 ± 0.6 % SpO2) and C values were 93.7 ± 8.4 mm Hg (95.4 ± 0.4 % SpO2) and 91.4 ± 5.4 mm Hg (94.8 ± 0.3 % SpO2). R ventilatory data described a significantly different breathing pattern than C, with higher respiratory rate (35.9 b · min-1 vs. 51.1 b · min-1 for C-R, p < 0.01; and 50.0 b · min-1 vs. 41.5 b · min-1 for R-C, p < 0.01) and lower tidal volume (2636 ml vs. 2282 ml for C-R, p < 0.02 and 2272 ml vs. 2472 ml for R-C, p < 0.05). We concluded that EIAH was greater during running than cycling for a similar metabolic rate corresponding to training intensity and that EIAH could thus be considered dependent on exercise modality.
Int J Sports Med 2005; 26: 719-726.