Bioquímica do Exercício

Deu no Medicine and Science in Sports and Exercise do ACSM, estudo realizado pelos patrícios da Univ do Porto. Acende uma polêmica no uso dos anti-oxidantes.

Purpose: This study aimed to determine the effects of 4 wk of antioxidants (AOX) supplementation on exercise-induced lipid peroxidation, muscle damage, and inflammation in kayakers. Methods: Subjects (n = 20) were randomly assigned to receive a placebo (PLA) or an AOX capsule (AOX; 272 mg of α-tocopherol, 400 mg of vitamin C, 30 mg of β-carotene, 2 mg of lutein, 400 μg of selenium, 30 mg of zinc, and 600 mg of magnesium). Blood samples were collected at rest and 15 min after a 1000-m kayak race, both before and after the supplementation period, for analysis of α-tocopherol, α-carotene, β-carotene, lycopene, lutein plus zeaxanthin, vitamin C, uric acid, total AOX status (TAS), thiobarbituric reactive acid substances (TBARS) and interleukin-6 (IL-6) levels, and creatine kinase (CK), superoxide dismutase (SOD), glutathione reductase (Gr), and glutathione peroxidase (GPx) activities. Results: With supplementation, plasma α-tocopherol (P = 0.003) and β-carotene (P = 0.007) augmented significantly in the AOX group. IL-6 (exercise, P = 0.039), TBARS (exercise, P < 0.001), and uric acid (exercise, P = 0.032) increased significantly in response to the exercise regardless of treatment group. Cortisol level raised more from pre- to postsupplementation period in the PLA group (time × supplementation, P = 0.002). Although TAS declined after exercise before intervention, it increased above preexercise values after the 4-wk period in the AOX group (supplementation × time × exercise, P = 0.034). CK increased after exercise in both groups (exercise effect, P < 0.001) and decreased from week 0 to week 4 more markedly in the PLA group (supplementation × time, P = 0.049). Conclusions: AOX supplementation does not offer protection against exercise-induced lipid peroxidation and inflammation and may hinder the recovery of muscle damage.

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