Effects of Maximal Static Apnea on Antioxidant Defenses in Trained Free Divers

• Autores: Andrew C. Bulmer, Jeff S. Coombes, James E. Sharman
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 40, Nº. 7, 2008, págs. 1307-1313
• Idioma: inglés
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• Resumen

  • Purpose: To investigate the effects of maximal static apnea on plasma antioxidant status, oxidative stress, and antioxidant enzyme activities in trained free divers.

    Methods: Blood was taken from apnea-trained (Tr) and control (Con) subjects at baseline (B) and after one (A1), three (A3), and five (A5) apneas. Trolox equivalent antioxidant capacity (TEAC), ferric reducing ability of plasma (FRAP), uric acid, and bilirubin assays assessed plasma antioxidant status and malondialdehyde (MDA) quantified the oxidative stress response. The activities of erythrocyte antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were determined at baseline and after the fifth apnea.

    Results: TEAC was significantly higher in divers versus controls after A1 (P < 0.05). A group effect of SOD activity indicated higher activity throughout the protocol in Tr (mean +/- SD; Con, 43.2 +/- 10.1 U[middle dot]g Hb-1; Tr, 50.1 +/- 7.3 U[middle dot]g Hb-1; P = 0.04). With no other group differences, the groups' data were combined. Apnea significantly increased SOD (B, 44.1 +/- 11.1 U[middle dot]g Hb-1; A5, 48.1 +/- 7.5 U[middle dot]g Hb-1; P < 0.05) and GPx activity (B, 60.5 +/- 14.9 U[middle dot]g Hb-1; A5, 70.1 +/- 16.0 U[middle dot]g Hb-1; P = 0.02); however, CAT activity decreased (B, 5.25 +/- 0.59 U[middle dot]mg Hb-1; A5, 5.00 +/- 0.53 U[middle dot]mg Hb-1; P = 0.03). MDA was unaffected by apnea (P = 0.32).

    Conclusions: Trained free divers have increased SOD activity during apnea; however, there is little difference in their antioxidant and oxidative stress responses compared with controls. In both groups, acute changes in antioxidant enzyme activities suggest that they may protect from excessive antioxidant depletion and oxidative stress during apnea.