title: [Young football players aerobic perfomance in sub-maximum exercise with exhaustion at a moderate altitude without acclimation: experience in El Condor].
abstract: BACKGROUND
  With the same intensity of sub-maximum effort, the concentration of serum (LS) or muscular lactate is higher in Hypoxia conditions, or exercise at an altitude without acclimation, in relation with normoxia or at sea level (MSL). The highest level of lactate after fatigue or in a test of strict anaerobic condition, would not be modified when altitude changes without previous acclimation.
  
  
  OBJECTIVE
  To abtain local data about the magnitude of the affect in SL of a effective altitude at 1,700 meters without acclimation, as a parameter of aerobic performance of young soccer players of our environment who live and train at sea level.
  
  
  METHODS
  Self-controlled experimental test with a number of 10 volunteers (16 - 18 years-old), soccer players of lower leagues from an important local sport club. Two tests in a cycle ergometer of a graded physical effort until fatigue, the first one in the Center of High Performance at MSL (474 meters) and the second one in the town El Condor (EC; 2.220 meters), province of Cordoba. Exercise Protocol: warm-up 2', 30 Km/h with 50W; 3consecutive steps of 3' + 50W each one; final phase 30 Km/h of 200W until fatigue and/or symptoms or maximum time of 15'. SL and HR measurement: basal; the last 30" of every step and in fatigue. SL determination with Accusport. Two-tailed paired test.
  
  
  RESULTS
  1 volunteer dropped out befote completion in EC (n=9). Mean basal SL 2.1 mmol/L at MSL and EC (p=0.897). Mean difference (MD) EC vs. MSL +/- Standard error of 0.5 +/- 0.2 (p=0.033), 0.9 +/- 0.3 (p=0.008) and 0.6 +/- 0.3 mmol/L (p=0.103) in steps 1, 2, 3 respectively of sub-maximum effort. In fatigue (the highest level), Mean SL and Confidence Interval (CI) 95% of 7.6 (6.5-8.8) and 9.5 (7.8-11.2) mmol/L at MSL and EC respectively (p=0.030). Heart Rhythm (HR) without changes in EC in relation to MSL. 66% with a greater Borg scale and 33% of dizziness at EC.
  
  
  CONCLUSIONS
  At an effective altitude at 1,700 meters without acclimation we can verify a lower aerobic performance with a subjective perception of a greater effort intensity, and neurological symptoms of hypoxia can be objectified in one-thirds of the cases.
authors.affiliation: Centro formador de Medicina del Deporte - Cátedra Medicina III - U.H.M.I. N- 3 - Hospital Córdoba.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Demo
authors.forename: Daniel
authors.initials: D
authors.lastname: Senestrari
authors.forename: Julio E
authors.initials: JE
authors.lastname: Ferreyra
mesh_terms: D000064:Acclimatization / Q000502:physiology*; D000293:Adolescent; D000531:Altitude; D015308:Anaerobic Threshold / Q000502:physiology; D001118:Argentina; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose; D015992:Body Mass Index; D003404:Creatinine / Q000097:blood; D017079:Exercise Tolerance / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D005082:Physical Exertion / Q000502:physiology; D012916:Soccer / Q000502:physiology*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D019344:Lactic Acid; D003404:Creatinine