Impairment of Anaerobic Capacity in Adults With Growth Hormone Deficiency

J Clin Endocrinol Metab. 2015 May;100(5):1811-8. doi: 10.1210/jc.2015-1006. Epub 2015 Feb 19.

Abstract

Context: The anaerobic energy system underpins the initiation of all physical activities, including those of daily living. GH supplementation improves sprinting in recreational athletes, a performance measure dependent on the anaerobic energy system. The physiological and functional link between GH and the anaerobic energy system is unknown.

Objective: The objective was to investigate whether anaerobic capacity is impaired in adults with GH deficiency (GHD) and to assess its functional significance.

Design: This was a cross-sectional study.

Participants: The participants were 13 adults with GHD and 13 age-, gender- and body mass index-matched normal subjects.

Main outcome measures: Anaerobic power (watts) was assessed by the 30-second Wingate test, and aerobic capacity was assessed by the VO2max (L/min) test. The functional assessment comprised the stair-climb test, chair-stand test, and 7-day pedometry. Quality of life (QoL) was assessed by the QoL-AGHDA questionnaire. Lean body mass (LBM) was quantified by dual-energy x-ray absorptiometry.

Results: Mean anaerobic power (5.8 ± 0.4 vs 7.1 ± 0.3 W · kg LBM(-1); P < .05) and VO2max were significantly lower in adults with GHD. The duration of the stair-climb test was longer (19.4 ± 0.7 vs 16.5 ± 0.7 s; P < .01) in adults with GHD and correlated negatively (R(2) = 0.7; P < .0001) with mean anaerobic power. The mean number of chair-stand repetitions and daily step counts were lower, and the QoL-AGHDA score was higher in adults with GHD (P < .05). In a multiple regression analysis, age, gender, LBM, and GH status were significant predictors of mean anaerobic power. Mean anaerobic power significantly predicted stair-climb performance (P < .01) and QoL (P < .05).

Conclusions: Anaerobic capacity is subnormal, and it independently predicts stair-climbing capacity and QoL in adults with GHD. We conclude that GH regulates anaerobic capacity, which determines QoL and selective aspects of physical function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anaerobic Threshold / physiology*
  • Body Composition / physiology*
  • Cross-Sectional Studies
  • Female
  • Human Growth Hormone / deficiency*
  • Humans
  • Hypopituitarism / metabolism*
  • Male
  • Middle Aged
  • Quality of Life
  • Young Adult

Substances

  • Human Growth Hormone