Publication | Closed Access
Growth hormone treatment in growth hormone-deficient adults. II. Effects on exercise performance
349
Citations
0
References
1991
Year
Physical ActivityMetabolic SyndromeKinesiologyBody CompositionBody MassExercisePhysical ExerciseApplied PhysiologyGrowth Hormone-deficient AdultsHealth SciencesLean Body MassGrowth HormonePhysical FitnessPediatric EndocrinologyEndocrinologyExercise SciencePhysiologyExercise PhysiologyGrowth Hormone TreatmentMetabolismMedicineExercise Performance
The study used a 6‑month double‑blind placebo‑controlled trial of recombinant human GH (0.07 U/kg/day) in 24 GH‑deficient adults, assessing exercise capacity with incremental cycle ergometry. rhGH increased lean body mass and thigh muscle cross‑sectional area, raised maximal VO₂max by 406 ml/min versus 133 ml/min (P = 0.016), raised maximal power output by 24.6 W versus 9.7 W (P = 0.047), and raised anaerobic ventilatory threshold by 159 ml/min versus 1 ml/min (P = 0.02), thereby normalizing submaximal exercise performance and suggesting that gains are related to muscle mass increases and possibly improved cardiac output.
Growth hormone (GH) treatment in adults with GH deficiency increases lean body mass and thigh muscle cross-sectional area. The functional significance of this was examined by incremental cycle ergometry in 24 GH-deficient adults treated in a double-blind placebo-controlled trial with recombinant DNA human GH (rhGH) for 6 mo (0.07 U/kg body wt daily). Compared with placebo, the rhGH group increased mean maximal O2 uptake (VO2max) (+406 +/- 71 vs. +133 +/- 84 ml/min; P = 0.016) and maximal power output (+24.6 +/- 4.3 vs. +9.7 +/- 4.8 W; P = 0.047), without differences in maximal heart rate or ventilation. Forced expiratory volume in 1 s, vital capacity, and corrected CO gas transfer were within normal limits and did not change with treatment. Mean predicted VO2max, based on height and age, increased from 78.9 to 96.0% in the rhGH group (compared with 78.5 and 85.0% for placebo; P = 0.036). The anaerobic ventilatory threshold increased in the rhGH group (+159 +/- 39 vs. +1 +/- 51 ml/min; P = 0.02). The improvement in VO2max was noted when expressed per kilogram body weight but not lean body mass or thigh muscle area. We conclude that rhGH treatment in adults with GH deficiency improves and normalizes maximal exercise performance and improves submaximal exercise performance and that these changes are related to increases in lean body mass and muscle mass. Improved cardiac output may also contribute to the effect of rhGH on exercise performance.