HÜTLER, M., D. SCHNABEL, D. STAAB, A. TACKE, U. WAHN, D. BÖNING, and R. BENEKE. Effect of growth hormone on exercise tolerance in children with cystic fibrosis. Med. Sci. Sports Exerc., Vol. 34, No. 4, pp. 567–572, 2002.
Purpose: The effect of growth hormone (GH) treatment on exercise tolerance in children with cystic fibrosis was investigated.
Methods: 10 prepubertal children (mean ± SD; age: 12.1 ± 1.7 yr; height: 137.4 ± 9.2 cm; body mass: 27.8 ± 4.2 kg; forced expiratory volume in 1 s (FEV1): 68 ± 22% predicted) were randomly assigned to either control period (CON, standard therapy) or recombinant human growth hormone (GH) period (additional GH treatment, 0.11-0.14 IU·kg−1, daily, s.c.) for the first 6 months, and then assigned to the other period for the next 6 months. At study entry and after each period, anthropometric data, pulmonary function, and exercise capacity (peak exercise capacity, V̇O2peak, and isokinetic muscle strength) were measured.
Results: Changes in height (+4.3 ± 1.0 cm), total body mass (+2.2 ± 0.8 kg), and lean body mass (LBM, +2.9 ± 0.7 kg) were significantly higher (P < 0.01) after GH treatment compared with CON. Pulmonary function did not significantly change in either of the periods. In contrast to CON, GH treatment improved absolute V̇O2peak (+19%, P < 0.01), peak ventilation (+14%, P < 0.01), and peak oxygen pulse (+18%, P < 0.01). Analysis of variance revealed that most of the changes (71%) in V̇O2peak could be explained by those in LBM and FEV1 (P = 0.001).
Conclusion: GH treatment clearly improved exercise tolerance, presumably resulting from the combined effects of GH on the muscular, cardiovascular, and pulmonary capacity.