title: Scuba diving increases erythrocyte and plasma antioxidant defenses and spares NO without oxidative damage.
abstract: OBJECTIVE
  The aim of the present work was to study the effects of a single scuba diving immersion to high depth on erythrocyte and plasma antioxidant defenses, on erythrocyte cellular damage, and on nitric oxide (NO) production.
  
  
  METHODS
  Seven male preprofessional divers performed an immersion at a depth of 40 m for a total time of 25 min. Blood samples were obtained before the diving session after overnight fasting, immediately after diving, and 3 h after the diving session was finished. Erythrocytes and plasma fractions were purified.
  
  
  RESULTS
  No significant differences were found in circulating erythrocytes, bilirubin, and hemoglobin concentration attributed to diving. Hematocrit levels were reduced after diving because of the reduction of erythrocyte size that was maintained after 3 h of recovery at the surface. Leukocyte counts significantly increased at recovery (38 +/- 4%). In erythrocytes, glutathione peroxidase activity significantly increased (18 +/- 4%) at recovery. A rise in plasma catalase activity (38 +/- 6%) immediately occurred after diving, returning to basal values after recovery. Plasma superoxide dismutase activity significantly increased (58 +/- 7%) during recovery. Markers of oxidative damage in both erythrocytes and plasma such as malondialdehyde and protein carbonyl derivates remained unchanged after diving. Nitrite levels significantly rose in plasma and erythrocytes (85 +/- 8% and 52 +/- 6%, respectively) at recovery.
  
  
  CONCLUSIONS
  Scuba diving session induced an antioxidant response in plasma and erythrocytes without the appearance of cellular damage and an increase in NO, which can be related with its vasodilator role.
authors.affiliation: Laboratory of Physical Activity Sciences, University of the Balearic Islands, Palma de Mallorca, Balearic Islands, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Sureda
authors.forename: Miguel D
authors.initials: MD
authors.lastname: Ferrer
authors.forename: Joan M
authors.initials: JM
authors.lastname: Batle
authors.forename: Pedro
authors.initials: P
authors.lastname: Tauler
authors.forename: Josep A
authors.initials: JA
authors.lastname: Tur
authors.forename: Antoni
authors.initials: A
authors.lastname: Pons
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000032:analysis*; D001663:Bilirubin / Q000097:blood; D015415:Biomarkers; D002374:Catalase / Q000097:blood; D004242:Diving; D004912:Erythrocytes; D006801:Humans; D006931:Hyperbaric Oxygenation; D015227:Lipid Peroxidation; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis* / Q000097:blood; D018384:Oxidative Stress; D011446:Prospective Studies; D017382:Reactive Oxygen Species
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D002374:Catalase; D001663:Bilirubin