title: Decreased anaerobic performance and hormone adaptation after expedition to Peak Lenin.
abstract: BACKGROUND
  The change of anaerobic exercise abilities during and after a high-altitude expedition or hypoxic exposure is not well studied. To evaluate the effects of an extreme-altitude expedition on anaerobic performance, the 10-second supramaximal test and endocrine hormones were evaluated before and after an expedition to Peak Lenin.
  
  
  METHODS
  Four subjects (3 male and 1 female, age (30.5 +/- 16.5) years) were recruited into the study. Three sets of tests were performed, including a basic test at sea level and 20 days before first arrival at the base camp (3600 m), a middle test done at day after returning from the summit to the base camp and the post test at the 10th day after return to the sea level. Both the supramaximal test, performed by a cycle ergometer, and body composition, performed by bioelectrical impedance analysis, were completed before the basic test and post test. The endocrine hormones including cortisol, growth hormone, testosterone, noradrenaline, adrenaline, dopamine, glucagon and beta-endorphin were measured at all tests.
  
  
  RESULTS
  Comparing the conditions before and after the expedition, the body measurement parameters were decreased after the expedition, i.e., body weight (-4.22%, P < 0.05), fat-free mass (-2.09%, P < 0.01) and body fat (-8.95%, P = 0.172). The peak power relative/body weight ratio (PP/BW) was similar ((9.70 +/- 1.97) vs (9.11 +/- 1.80) W/kg, P = 0.093), while mean power/body weight ratio (MP/BW) was reduced significantly after the expedition ((9.14 +/- 1.77) vs (8.33 +/- 1.74) W/kg, P < 0.05). Peak power/fat-free mass (PP/FFM), mean power/fat-free mass (MP/FFM) and fatigue index (FI) were significantly lower after the expedition (PP/FFM: (11.95 +/- 1.71) vs (10.99 +/- 1.59) W/kg, P < 0.05; MP/FFM: (11.26 +/- 1.50) vs (10.04 +/- 1.55) W/kg, P < 0.005; FI (85.55 +/- 4.17)% vs (77.25 +/- 4.40)%, P < 0.05). Hormone assays showed a significant increase of noradrenaline (basic vs middle, P < 0.05) as well as decrease of adrenaline (P < 0.05). Meanwhile, a trend towards an increase in dopamine (basic vs middle) and a decrease of beta-endorphin (basic vs post) were also noted.
  
  
  CONCLUSIONS
  These results suggested that an expedition to an extreme altitude may have negative effects on anaerobic performance. It showed that a significant increase of noradrenaline (basic vs middle) as well as decrease of adrenaline after the expedition to Peak Lenin had occurred. The real physiological significance needs to be further investigated.
authors.affiliation: College of Humanities, Social and Natural Sciences, Ming Hsin University of Science and Technology, Hsinchu 304, Taiwan, China.
authors.forename: Kung-tung
authors.initials: KT
authors.lastname: Chen
authors.forename: Yu-yawn
authors.initials: YY
authors.lastname: Chen
authors.forename: Huey-june
authors.initials: HJ
authors.lastname: Wu
authors.forename: Chen-kang
authors.initials: CK
authors.lastname: Chang
authors.forename: Wen-tsung
authors.initials: WT
authors.lastname: Lee
authors.forename: Yen-yuan
authors.initials: YY
authors.lastname: Lu
authors.forename: Chieh-chung
authors.initials: CC
authors.lastname: Liu
authors.forename: Rong-sen
authors.initials: RS
authors.lastname: Yang
authors.forename: Jung-charng
authors.initials: JC
authors.lastname: Lin
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000531:Altitude; D015308:Anaerobic Threshold / Q000502:physiology*; D004298:Dopamine / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005080:Exercise Test; D005260:Female; D005934:Glucagon / Q000097:blood; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D013739:Testosterone / Q000097:blood; D055815:Young Adult; D001615:beta-Endorphin / Q000097:blood
chemical_list: D013739:Testosterone; D001615:beta-Endorphin; D013006:Growth Hormone; D005934:Glucagon; D004298:Dopamine; D006854:Hydrocortisone; D009638:Norepinephrine; D004837:Epinephrine