Evidence of Exercise-Induced Arterial Hypoxemia in Prepubescent Trained Children

Abstract

Exercise-induced arterial hypoxemia (EIAH) is a recognized phenomenon in highly trained adults. Like adult athletes, prepubescent trained children may develop high-level metabolic demand but with a limited lung capacity in comparison with adults. The purpose of this investigation was to search for evidence of EIAH in prepubescent trained children. Twenty-four prepubescent (age: 10.3 Ϯ 0.2 y) trained children (10.0 Ϯ 0.7 h of weekly physical activity) performed pulmonary function tests and a graded maximal exercise test on a cycle ergometer. EIAH was defined as a drop of at least 4% from resting level arterial oxygen saturation (SaO 2 ) measured by pulse oximetry. EIAH was observed in seven children. Forced vital capacity (FVC), ventilatory response to exercise (⌬V E /⌬V CO 2 ), and breathing reserve at maximal exercise were significantly lower, whereas tidal volume relative to FVC was higher in hypoxemic children than in nonhypoxemic children; weekly physical activity and maximal oxygen uptake were similar. Moreover, positive relationships were found between SaO 2 at maximal exercise and breathing reserve (r ϭ 0.56; p Ͻ 0.05) or volume relative to FVC (r ϭ 0.70; p Ͻ 0.01). EIAH may occur in prepubescent trained children with a relatively low maximal oxygen uptake (42 mL · min Ϫ1 · kg Ϫ1 ); however, the mechanisms remain unclear and need to be investigated more accurately. Healthy individuals are commonly considered to be able to maintain arterial oxygenation to meet the increased metabolic demand induced by exercise at sea level. It now is widely recognized, however, that some highly trained adult athletes may reach the limits of their pulmonary function during exercise (1-5). Impaired pulmonary gas exchange leading to exercise-induced arterial hypoxemia (EIAH), characterized by a fall-off of both partial arterial oxygen (PaO 2 ) and arterial oxygen saturation (SaO 2 ) below resting values, is ample evidence (2,3,5). This phenomenon may reduce aerobic performance in these athletes (2,3,5,6).EIAH is a multifactorial phenomenon and may be explained in adults by 1) a relative alveolar hypoventilation (7,8), 2) an increase of ventilation-perfusion inequality (V A/Q c) (9, 10), and/or 3) an alveolar to capillary diffusion limitation during exercise (5, 9, 10). Moreover, in adult women, pulmonary gas exchanges may be altered by a reduced lung size (4, 10, 11). Indeed, a high alveolar-arterial oxygen tension difference during exercise seems to be due to inadequate pulmonary structure/function in women who experience significant EIAH at maximal oxygen uptake (V O 2max ) (4,11

Maximal Oxygen Uptake Validation in Children With Expiratory Flow Limitation

“…herein is whether children who demonstrate EIAH (27) can perform the two-test protocol successfully. This was because all children maintained arterial oxygenation throughout the tests and thus, the possibility that EIAH might contribute to fatigue and preclude an individual from cycling for sufficient duration at 105% of the peak IWT power cannot be dismissed at this time.…”

“…What has not been established in children is whether this procedure is effective across the spectrum of lower fitness levels as might be expected in a randomly recruited population, for example, in the United States. It is also pertinent that among this population of prepubescent children there may be a high prevalence of expiratory flow limitation (EFL, 28,29,40) and possibly exercise-induced arterial hypoxemia (EIAH,27). Whether the two-test protocol can effectively determine VO 2 max across a broad spectrum of fitness levels and in the presence of EFL in children which, in and of itself may increase fatigability and modulate the respiratory response to exercise, has not been determined.…”

Difference in breathing strategies during exercise between trained elderly men and women

“…VE and . VCO 2 recorded between the onset of exercise and the occurrence of the respiratory compensation point (Nourry et al, 2004;Deruelle et al, 2006). The respiratory compensation point, i.e.…”

Comparison of VO2 Max Prediction Value, Physiological Response, and Borg Scale between 12-Minute and 3200-Meter Run Fitness Tests among Indonesian Army Soldiers

“…16 The oxygen saturation decrement with oxymetry pulse measurement may imply exercise-induced hypoxemia. 17 A study found that hypoxemia occurs when SpO 2 is decreasing from 97% to 92%. 18 Another study also reported that minor exercise-induced hypoxemia may occur when the SpO 2 decreases to 93-95% (3-4%) since resting, from resting with the moderate occurs in 88-92% since resting and the major one occurs when a decrease from 88% happens.…”