University Of Tasmania

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Effects of maximal static apnea on antioxidant defenses in trained free divers

journal contribution
posted on 2023-05-17, 01:37 authored by Bulmer, A, Coombes, JS, James SharmanJames Sharman, Stewart, I
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 AI (P < 0.05). A group effect of SOD activity indicated higher activity throughout the protocol in Tr (mean ± SD; Con, 43.2 ± 10.1 Ug Hb-1; Tr, 50.1 ± 7.3 U·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 Ug Hb -1; A5, 48.1 ± 7.5 Ug Hb-1; P < 0.05) and GPx activity (B, 60.5 ± 14.9 Ug Hb-1; A5, 70.1 ± 16.0 Ug Hb-1; P = 0.02); however, CAT activity decreased (B, 5.25 ± 0.59 Umg Hb-1; A5, 5.00 ± 0.53 Umg 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.


Publication title

Medicine and Science in Sports and Exercise










Menzies Institute for Medical Research


Lippincott Williams & Wilkins

Place of publication

530 Walnut St, Philadelphia, USA, Pa, 19106-3621

Repository Status

  • Restricted

Socio-economic Objectives

Clinical health not elsewhere classified

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