Key result
Breathing 21% or 100% O2 did not increase leg VO2max relative to 15% O2 in sedentary subjects, but 12% O2 reduced it, confirming muscle VO2max is O2 supply limited only in hypoxia.
Why the study?
Does altering FIO2 affect leg VO2max during maximal cycle ergometry in sedentary subjects?
Population
24 completely sedentary normal young subjects
Comparison
Breathing different fractions of inspired oxygen… vs Different FIO2 levels compared to each other
Design
Other
Authors
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Hyperoxia does not enhance leg VO2max in normoxic sedentary subjects; leaves open mitochondrial limitation in trained or clinical cohorts.
Does altering FIO2 affect leg VO2max during maximal cycle ergometry in sedentary subjects?
In sedentary subjects, muscle VO2max is limited by O2 supply only in hypoxia, suggesting oxidative capacity of mitochondria is the limiting factor in normoxia.
S et al. (1998) studied Sedentary normal young subjects (n=24). Different fractions of inspired oxygen (FIO2) vs. FIO2 of 0.15 was evaluated on leg VO2max (VO2leg). Breathing 21% or 100% O2 did not increase leg VO2max relative to 15% O2 in sedentary subjects, but 12% O2 reduced it, confirming muscle VO2max is O2 supply limited only in hypoxia.
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