title: Growth hormone responses to repeated bouts of aerobic exercise with different recovery intervals in cyclists.
abstract: To characterise the specific GH responses to repeated bouts of standardised aerobic exercise in amateur competitive cyclists, 6 volunteers (mean age +/- SE: 28.7 +/- 2.3 yr, range: 18-35 yr) performed two consecutive 30-min cycling sessions at 80% of individual maximal oxygen uptake on three occasions with different time interval between bouts: 2 h (EXP A), 4 h (EXP B) and 6 h (EXP C). Serum GH concentration was determined in blood samples collected at 15-min intervals during exercise and following 1 h of recovery. In EXP A and EXP B, peak GH concentration in response to the second bout was significantly lower (p < 0.01) than that of the first bout, but in EXP C no difference was detected between bouts. Similarly, the average integrated GH concentration (AUC), determined during the exercise period and in the following 1 h of recovery in the course of the second bout, was significantly lower than that observed during the first bout only in EXP A (p < 0.05) and EXP B (p < 0.01) and not in EXP C, so that the second bout AUC of EXP C was significantly higher than that of EXP A (p < 0.01) and EXP B (p < 0.01). It was concluded that GH responses to subsequent bouts of aerobic exercise are dependent on the time interval between the exercise sessions.
authors.affiliation: 3rd Division of Metabolic Diseases, Italian Institute for Auxology, IRCCS, Milano, Italy. sartorio@auxologico.it
authors.forename: A
authors.initials: A
authors.lastname: Sartorio
authors.forename: F
authors.initials: F
authors.lastname: Agosti
authors.forename: P G
authors.initials: PG
authors.lastname: Marinone
authors.forename: M
authors.initials: M
authors.lastname: Proietti
authors.forename: C L
authors.initials: CL
authors.lastname: Lafortuna
mesh_terms: D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D019382:Human Growth Hormone / Q000097:blood* / Q000378:metabolism*; D006801:Humans; D008297:Male
chemical_list: D019382:Human Growth Hormone