Short-term recombinant human growth hormone administration improves respiratory function in abstinent anabolic–androgenic steroid users

Objectives
To determine whether 6 days recombinant human growth hormone (rhGH) administration, in an abstinent anabolic–androgenic steroid (AAS) using group had any respiratory, endurance exercise and biochemical effects compared with an abstinent AAS control group. 
Methods 
Male subjects (n = 48) were randomly divided, using a single blind procedure into two groups: (1) control group (C) n = 24, means ± SD, age 32 ± 11 years; height 1.8 ± 0.06 m; (2) rhGH using group (0.019 mg kg−1 day−1) (GH) n = 24, means ± SD, age 32 ± 9 years; height 1.8 ± 0.07 m. Anthropometry, respiratory muscle function and endurance exercise were investigated. Respiratory measurements examined, were forced expiratory volume in one second, forced vital capacity, maximum inspiratory pressure and maximum expiratory pressure. Endurance exercise was assessed by measuring peak oxygen uptake (VO2peak). Biochemical analysis included; haemoglobin, packed cell volume, glucose, sodium, urea, creatinine, total protein, albumin, testosterone and insulin like growth factor-I (IGF-I). 
ResultsForced expiratory volume in one second/forced vital capacity, maximum inspiratory pressure, maximum expiratory pressure, and IGF-I significantly increased compared with the control group (all P < 0.05). 
Body mass index, fat free mass index, peak oxygen uptake, maximum inspiratory pressure, maximum expiratory pressure, IGF-I and serum sodium significantly increased, whilst body fat, total protein and albumin, significantly decreased within the GH group (all P < 0.017). 
Conclusion 
The findings of this study indicated that short-term high dose rhGH increased aerobic performance and respiratory muscle strength in former AAS users.