title: Comparison of the hormonal responses to exhaustive incremental exercise in adolescent and young adult males.
abstract: OBJECTIVE
  Evaluate hormonal responses to incremental-stage exercise (EX) test to exhaustion in adolescents.
  
  
  METHODS
  Adolescents were tested at 16 years of age in Tanner Stage 4 (TS4) and at 17 years of age in Tanner Stage 5 (TS5) (n = 6). Adults were tested at 21 ± 1 y. (X ± SD) (n = 4) and served as controls. Blood samples were taken at rest, at the end of each EX stage.
  
  
  RESULTS
  Main effects for EX in cortisol (p < 0.01, increasing with each EX stage) and for subject group for testosterone (T) occurred (p < 0.01; TS4 < TS5, adults). Interaction effect of group by EX stage occurred for GH (p < 0.05). GH increased in response to EX in all groups, however, the magnitude of increase was significantly less for TS5 and adults than TS4.
  
  
  CONCLUSIONS
  Differences in T and GH responses for TS4 than those for TS5 and adults reflect the differing maturation levels of the endocrine system between Tanner Stages. TS5 adolescents are more similar to young adults in hormonal responses to EX than are TS4 adolescents.
authors.affiliation: Endocrine Section, Applied Physiology Laboratory, University of North Carolina, Chapel Hill, 27599, USA. ach@email.unc.edu
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Hackney
authors.forename: Mehis
authors.initials: M
authors.lastname: Viru
authors.forename: Mitch
authors.initials: M
authors.lastname: VanBruggen
authors.forename: Tamara
authors.initials: T
authors.lastname: Janson
authors.forename: Kalle
authors.initials: K
authors.lastname: Karelson
authors.forename: Atko
authors.initials: A
authors.lastname: Viru
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology*; D006728:Hormones / Q000097:blood* / Q000145:classification; D006801:Humans; D008297:Male; D005082:Physical Exertion / Q000502:physiology*; D012146:Rest / Q000502:physiology; D055815:Young Adult
chemical_list: D006728:Hormones