Favier F B, Prieur F, Grataloup O, Busso T, Castells J, Denis C, Geyssant A, Benoit H
Unité de recherche Physiologie et Physiopathologie de l'Exercice et Handicap, Faculté de Médecine Saint Etienne, Université Jean Monnet, France.
Eur J Appl Physiol. 2005 May;94(1-2):107-12. doi: 10.1007/s00421-004-1310-3. Epub 2005 Jan 29.
Few studies evidenced an enhancement in oxygen uptake (VO2) during submaximal exercise in hyperoxia. This O2 "overconsumption" seems to increase above the lactate threshold. The aim of this study was to determine whether the hyperoxia-induced enhancement in VO2 may be related to a higher metabolism of lactate. Nine healthy males (aged 23.1 years, mean VO2 max= 53.8 ml min-1 kg-1) were randomized to two series of exercise in either normoxia or hyperoxia corresponding to an inspired O2 fraction (FIO2) of 30%. Each series consisted of 6 min cycling at 50% VO2 max (Moderate1), 5 min cycling at 95%VO2 max (Near Max) and then 6 min at 50% VO2 max (Moderate2). In both series Near Max was performed in normoxia. VO2 was significantly greater under hyperoxia than in normoxia during Moderate1 (2192 +/- 189 vs. 2025 +/- 172 ml min-1) and during Moderate2 (2352 +/- 173 vs. 2180+ /- 193 ml min-1). However, the effect of the high FIO2 was not significantly different on VO2Moderate2 (+172+/-137 ml min-1 with [La] approximately 6 mmol l-1) compared to VO2Moderate1 (+166 +/- 133 ml min-1 with [La] approximately 2.4 mmol l-1). [La] at the onset of Moderate2 was not different between normoxia and hyperoxia (10.1 +/- 2.2 vs. 10.9 +/- 1.6 mmol l-1). The results show that VO2 is significantly increased during moderate exercise in hyperoxia. But this O2 overconsumption was not modified by a high [La] induced by a prior heavy exercise. It could be concluded that lactate accumulation is not directly responsible for the increase in O2 overconsumption with intensity during exercise in hyperoxia.
很少有研究证明在高氧环境下进行次最大运动时摄氧量(VO₂)会增加。这种氧气的“过度消耗”似乎在乳酸阈以上会增加。本研究的目的是确定高氧诱导的VO₂增加是否可能与乳酸的更高代谢有关。九名健康男性(年龄23.1岁,平均VO₂ max = 53.8 ml min⁻¹ kg⁻¹)被随机分为两组,分别在常氧或高氧环境下进行两轮运动,高氧环境下吸入氧分数(FIO₂)为30%。每轮运动包括以50% VO₂ max进行6分钟骑行(中度1)、以95% VO₂ max进行5分钟骑行(接近最大值),然后再以50% VO₂ max进行6分钟骑行(中度2)。在两轮运动中,接近最大值的骑行均在常氧环境下进行。在中度1期间(2192 ± 189 vs. 2025 ± 172 ml min⁻¹)和中度2期间(2352 ± 173 vs. 2180 ± 193 ml min⁻¹),高氧环境下的VO₂显著高于常氧环境。然而,与中度1([La]约为2.4 mmol l⁻¹时VO₂增加166 ± 133 ml min⁻¹)相比,高FIO₂对中度2([La]约为6 mmol l⁻¹时VO₂增加172 ± 137 ml min⁻¹)时VO₂的影响无显著差异。中度2开始时的[La]在常氧和高氧环境下无差异(10.1 ± 2.2 vs. 10.9 ± 1.6 mmol l⁻¹)。结果表明,在高氧环境下进行中度运动时VO₂显著增加。但这种氧气的过度消耗并未因先前剧烈运动诱导的高[La]而改变。可以得出结论,在高氧环境下运动时,乳酸积累并非导致氧气过度消耗随运动强度增加的直接原因。