Why the study?
Does hyperoxia alter metabolic and hormonal responses during submaximal exercise at the same absolute or relative power outputs in college-aged males?
Does hyperoxia alter metabolic and hormonal responses during submaximal exercise at the same absolute or relative power outputs in college-aged males?
Hyperoxia alters metabolic and hormonal responses during submaximal exercise at the same absolute power output, but these differences disappear when exercising at the same relative power output.
Should not yet change exercise testing protocols; leaves open applicability of relative-intensity matching beyond healthy males.
Maximum oxygen uptake (VO2max) was measured in six college-aged males under normoxic (NVO2max) and hyperoxic (HVO2max; 70% oxygen) conditions. Subjects then randomly performed the following three 20-min submaximal exercise bouts: 75% normoxic VO2max under normoxia (NVO2N), 75% normoxic VO2max under hyperoxia (NVO2H), and 75% hyperoxic VO2max under hyperoxia (HVO2H). Metabolic parameters were obtained at 5-min intervals. Hyperoxia resulted in a 13% increase (P less than 0.01) in VO2max (NVO2max = 3.54 l X min-1 vs HVO2max = 4.00 l X min-1). Significant (P less than 0.05) decreases were observed in VE (ventilation) (13%), epinephrine (37%), norepinephrine (26%), and blood lactate (28%), with no change in oxygen uptake (VO2), carbon dioxide production (VCO2), or respiratory exchange ratio (R) during hyperoxia at the same absolute power output (NVO2N vs NVO2H). However, at the same relative power outputs (NVO2N vs HVO2H) no significant changes in VE, epinephrine, norepinephrine, or blood lactate were observed when hyperoxia and normoxia were compared.
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Byrnes et al. (1984) studied this question.
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