You may have seen athletes using oxygen masks to help them recover from extreme bouts of exercise.Getting oxygen in the blood is great for recovery from aerobic exercise, but whether these benefits extend to resistance training is a topic of some uncertainty. A study this month in the Journal of Strength and Conditioning Research looked at increasing oxygen levels as a means of improving recovery in athletes.
Theoretically, oxygen works to alleviate peripheral fatigue (the causes of muscle fatigue that aren’t in the CNS) by more effective treatment of the acidosis that results from exercise. Acidosis means that the body has become more acidic than normal, and so cannot function optimally. Acidosis is often associated with muscle fatigue. Because greater oxygen can help your cells remove acid, it makes sense that it might also help athletes recover faster from exercise.
The problem with researching oxygen treatment for athletes so far has been inconsistency. In theory, oxygen should alleviate fatigue, so more oxygen must be better, but it isn’t always the case. According to the authors of this study, treatments of 100% oxygen that were used in previous studies have often had no effect on acidosis, and various levels of oxygen have had unpredictable effects on perceived fatigue.
So in this study, the researchers kept the conditions basic. They compared the recovery effects of two oxygen conditions on isometric contractions of the quads. One condition was that of the normal air we breathe, which contains about 20.9% oxygen. The other condition was hyperoxic, meaning that it had more oxygen than normal air. The hyperoxic condition contained 30% oxygen, so was only slightly greater than normal.
The participants in the study did three sets of isometric contractions of the quads. Each set was separated by lengthy fifteen-minute recovery periods. During these recovery periods, the participants received one of the two oxygen treatments. The researchers looked at the athletes’ blood lactate levels as a measure of acidosis, as well as their perceived exertion. Both of these variables have been proposed to be altered by increased oxygen in the air.
Here’s the curveball. Hyperoxia did not alter the lactate levels or the perceived exertion, but it did alter performance. Performance was improved with more oxygen by 14% on the third set. It’s possible that the full exposure of thirty minutes (the two fifteen-minute rest periods) is necessary for performance enhancement.
So, although the researchers were correct insofar as performance was improved, exactly how that happens remains uncertain, since lactate levels were unaffected. Whatever the reason, it seems that slightly elevated oxygen levels are effective in aiding recovery.
References:
1. Yuka Yokoi, et. al., “Recovery Effects of Repeated Exposures to Normobaric Hyperoxia on Local Muscle Fatigue,” Journal of Strength and Conditioning Research, DOI: 10.1519/JSC.0000000000000386
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