title: Plasma nitrite/nitrate and erythropoietin levels in cross-country skiers during altitude training.
abstract: BACKGROUND
  The aim of this study was to evaluate the effects of training at altitude on plasma nitrite/nitrate and erythropoietin levels since previously it has been reported an interaction of the NO/cGMP system in erythropoietin production.
  
  
  METHODS
  Nine physically trained cross-country male skiers, usually living at 800-1200 m altitude, underwent 6 days of intensive training at a moderate altitude of 3100 m preceeded by 2 days of acclimatisation. Six team-managers, selected as controls, did not undergo any regular physical activity in the last 5 years and during the altitude period. Haematological parameters, erythropoietin and nitrite/nitrate were measured prior to reach the place at altitude, at the end of the period at moderate altitude and 7 days after returning at home.
  
  
  RESULTS
  Haematocrit significantly increased in controls after 8 days at altitude. Erythropoietin levels significantly increased after the intensive altitude training only in trained subjects (13.1+/-1.7 vs 6.7+/-1.7 mU x ml-1, p<0.001). Nitrite/nitrate baseline values were significantly higher in trained subjects compared to untrained (49.9+/-17.9 vs 25.4+/-2.8 micromol x l(-1), p<0.01); the altitude period significantly increased nitrite/nitrate levels, in untrained subjects, to the same values observed in trained subjects under control conditions (47.0+/-10.3 micromol x l(-1)).
  
  
  CONCLUSIONS
  In our experimental conditions we demonstrated the influence of hypoxia on Epo levels in athletes sustaining a short-term training and the role of a regular physical activity (partly independent from altitude hypoxia) on NO production.
authors.affiliation: Ce.Bi.S.M., Center of Bioengineering and Motor Sciences, Rovereto (TN), Italy.
authors.forename: F
authors.initials: F
authors.lastname: Schena
authors.forename: L
authors.initials: L
authors.lastname: Cuzzolin
authors.forename: L
authors.initials: L
authors.lastname: Rossi
authors.forename: M
authors.initials: M
authors.lastname: Pasetto
authors.forename: G
authors.initials: G
authors.lastname: Benoni
mesh_terms: D000328:Adult; D000531:Altitude; D000704:Analysis of Variance; D004920:Erythropoiesis / Q000502:physiology*; D006400:Hematocrit; D006801:Humans; D000860:Hypoxia / Q000097:blood; D008297:Male; D009569:Nitric Oxide / Q000097:blood*; D010809:Physical Fitness / Q000502:physiology*; D012865:Skiing
chemical_list: D009569:Nitric Oxide