title: Age is an important determinant of the growth hormone response to sprint exercise in non-obese young men.
abstract: BACKGROUND
  The factors that regulate the growth hormone (GH) response to physiological stimuli, such as exercise, are not fully understood. The aim of the present study is to determine whether age, body composition, measures of sprint performance or the metabolic response to a sprint are predictors of the GH response to sprint exercise in non-obese young men.
  
  
  METHODS
  Twenty-seven healthy, non-obese males aged 18-32 years performed an all-out 30-second sprint on a cycle ergometer. Univariate linear regression analysis was employed to evaluate age-, BMI-, performance- and metabolic-dependent changes from pre-exercise to peak GH and integrated GH for 60 min after the sprint.
  
  
  RESULTS
  GH was elevated following the sprint (change in GH: 17.0 +/- 14.2 microg l(-1); integrated GH: 662 +/- 582 min microg l(-1)). Performance characteristics, the metabolic response to exercise and BMI were not significant predictors of the GH response to exercise. However, age emerged as a significant predictor of both integrated GH (beta = -0.547, p = 0.003) and change in GH (beta = -0.448, p = 0.019) after the sprint.
  
  
  CONCLUSIONS
  In non-obese young men, age is a more important predictor of GH following sprint exercise than BMI, sprint performance or the metabolic response to sprint exercise.
authors.affiliation: Sport and Exercise Science Group, School for Health, University of Bath, Bath, UK. k.stokes@bath.ac.uk
authors.forename: Keith
authors.initials: K
authors.lastname: Stokes
authors.forename: Mary
authors.initials: M
authors.lastname: Nevill
authors.forename: George
authors.initials: G
authors.lastname: Hall
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001823:Body Composition; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D008297:Male
chemical_list: D019382:Human Growth Hormone