Antioxidant status of elite athletes remains impaired 2 weeks after a simulated altitude training camp
 
 
Journal Title (Medline/Pubmed accepted abbreviation): Eur J Nutr
Year:   2010
Volume: 49
Number: 
Page numbers: 285-292
doi (if applicable): 

Summary of Background and Research Design

Hypothesis: The hypothesis was that antioxidant status is impaired by 18 days of “living high, training low” (LHTL) and will remain altered after 14 days of recovery.

Subjects: A total of 11 elite cross-country skiers were the subjects in this study. There were 6 in the treatment group (3 male, 3 female) and 5 (2 male, 3 female) in the control group. Subjects were not taking antioxidant supplements during training and recovery periods.

Experimental design: Independent groups (no crossover), subjects were matched on VO2 max upon assignment to treatment groups. 

Treatments and protocol: Following pre-testing, the subjects in the treatment group trained for 2 hours per day in a camp at Prémanon, France (altitude 1,200 m) for a period of 18 days. During this period, their resting and sleeping periods were spent at a simulated higher altitude in a controlled chamber in which normobaric poikilocapnic hypoxia was achieved. The chamber was set to simulate 2,500 m for the first 6 nights, then 3,000 m for 6 nights and 3,500 m for 6 nights. Oxygen saturation of the athletes was monitored for safety. The control group performed the same training routine in the same location with no hypoxia. Following the training period, all subjects recovered for a 14-day period at 1,200 m. Blood sampling was done at pretest and at days 1 (POST1) and 14 (POST14) posttraining for various markers of oxidative status and levels of antioxidant nutrients such as vitamin E, vitamin A, lycopene, and b-carotene.

Summary of research findings:
  • Advanced oxidation protein products (AOPP) were elevated in the treatment group  after the first day of living and training under hypoxic conditions (POST 1), although they appeared to be normalized by day 14 (POST 14). 
  • The trolox equivalent antioxidant capacity (TEAC) was decreased at POST1, but also improved toward pretest values by POST 14 in the treatment group. 
  • Levels of ferric reducing antioxidant power (FRAP), lycopene, and b-carotene were all significantly reduced at POST1 and had not recovered to pretest values by POST14 in the treatment group.
  • The control group experienced significant declines in FRAP and TEAC at POST1, but the values rebounded to near pretest levels by POST 14.
  •  Dietary intakes of vitamin E were significantly higher in the control group versus treatment group during the training period, but the vitamin E intakes were still below the Recommended Dietary Allowance (RDA) for both groups (85% and 53% of RDA, respectively). There were no differences between groups for vitamin E intake during the recovery period, although both were still well below RDA levels.
  •  The authors also expressed concern that while the intakes of vitamins A and C might have met their countries RDAs for sedentary individuals, the intakes may have been insufficient for their high level of activity (self-reported energy intake was about 3,000 kcal/day).

Interpretation of findings/Key practice applications:

 The authors showed that for some markers of antioxidant status, even 14 days of recovery at lower altitude was insufficient to return these markers to the levels observed before exposure to higher altitude occurred. The authors postulated that perhaps the dietary intake of antioxidant nutrients was insufficient to compensate for the oxidant stress induced by altitude and training in these athletes. Further studies are required to examine if supplementation of antioxidant nutrients in such athletes will prevent these declines in antioxidant status.
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