Effects of antioxidant supplementation on exercise performance in acute normobaric hypoxia.
OBJECTIVE
To compare the effects of a 3-week supplementation between two different mixtures of antioxidants and placebo on aerobic exercise performance in acute normobaric hypoxia.


METHODS
Seventeen subjects were randomly assigned in a double-blind fashion to receive a broad-based antioxidants supplement containing beta-carotene, ascorbic acid, d-alpha-tocopherol-succinate, N-acetylcysteine, riboflavin, zinc, and selenium (antioxidant capsule group [AO group]), or a combination of alpha-ketoglutaric acid (α-KG) and 5-hydroxymethylfurfural (5-HMF; CYL concentrate supplementation group [CS group]), or placebo (PL group). Before and after supplementation, subjects performed two incremental cycle-exercise tests until exhaustion. The first test was conducted under normoxic conditions (LA, FiO2 of 20.9%, ~547 m) and the second after the 3-week supplementation period under normobaric hypoxic conditions (AHA, FiO2 of 12.9%, ~4300m).


RESULTS
In CS peak cycling performance (peak power) declined from LA to AHA 7.3% (90% CI: 2.2-12.4) less compared with PL (p = .04) and 6.7% (90%CI: 3.2-10.2) less compared with AO (p = .03). Better maintenance of aerobic exercise capacity in CS was associated with an attenuated reduction in maximal heart rate in hypoxia.


CONCLUSIONS
Aerobic exercise performance was less impaired in acute normobaric hypoxia after 3 weeks with supplementation of α-KG and 5-HMF compared with a broad-based antioxidants supplement or PL.
Dept. of Sports Science, Medical Section, University of Innsbruck, Austria.
Christian
C
Mariacher
Hannes
H
Gatterer
Joachim
J
Greilberger
Radoslav
R
Djukic
Michaela
M
Greilberger
Marc
M
Philippe
Martin
M
Burtscher
D000328:Adult; D000975:Antioxidants / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D004338:Drug Combinations; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005662:Furaldehyde / Q000031:analogs & derivatives* / Q000494:pharmacology; D006339:Heart Rate; D006801:Humans; D000860:Hypoxia; D007656:Ketoglutaric Acids / Q000494:pharmacology*; D008297:Male; D018977:Micronutrients / Q000494:pharmacology*; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects; D010809:Physical Fitness / Q000502:physiology; D055815:Young Adult
D000975:Antioxidants; D004338:Drug Combinations; D007656:Ketoglutaric Acids; D018977:Micronutrients; C008046:5-hydroxymethylfurfural; D005662:Furaldehyde