Effects of Growth Hormone Administration on Muscle Strength in Men over 50 Years Old.

Growth hormone (GH) use has been speculated to improve physical capacity in subjects without GH deficiency (GHD) through stimulation of collagen synthesis in the tendon and skeletal muscle, which leads to better exercise training and increased muscle strength. In this context, the use of GH in healthy elderly should be an option for increasing muscle strength. Our aim was to evaluate the effect of GH therapy on muscle strength in healthy men over 50 years old. Fourteen healthy men aged 50-70 years were evaluated at baseline for body composition and muscle strength (evaluated by leg press and bench press exercises, which focus primarily on quadriceps-lower body part and pectoralis major-upper body part-muscles, resp.). Subjects were randomised into 2 groups: GH therapy (7 subjects) and placebo (7 subjects) and reevaluated after 6 months of therapy. Thirteen subjects completed the study (6 subjects in the placebo group and 7 subjects in the GH group). Subjects of both groups were not different at baseline. After 6 months of therapy, muscle strength in the bench press responsive muscles did not increase in both groups and showed a statistically significant increase in the leg press responsive muscles in the GH group. Our study demonstrated an increase in muscle strength in the lower body part after GH therapy in healthy men. This finding must be considered and tested in frail older populations, whose physical incapacity is primarily caused by proximal muscle weakness. The trial was registered with NCT01853566.

Is there a relationship between spontaneous GH secretion, anthropometric parameters and exercise capacity in healthy men over 50 years?

BACKGROUND: The use of growth hormone (GH) in deficient adults has already been demonstrated to result in several benefits regarding metabolic parameters, body composition and quality of life. Due to the similarities between GH deficiency in adults and the aging process, the concept of somatopause has emerged. OBJECTIVES: Correlate the GH secretion profile in healthy men older than 50 years with anthropometric parameters and exercise capacity. PATIENTS AND METHODS: Twenty-nine healthy male were selected, with a mean age of 57.9+/-4.2 years (range 50-66). After hospital admission, body mass index (BMI), body composition (fat mass) and abdominal circumference, 24-h GH profile, GH peak and basal IGF-I were evaluated, and all the patients underwent a treadmill stress testing to estimate exercise capacity with the Bruce protocol, with evaluation of the maximum oxygen peak, maximum heart rate and METs. All the results are shown as mean+/-Std deviation: BMI -26.5+/-4.9kg/m2, percent fat mass -27.1+/-6.2%, abdominal circumference -92.1+/-10.1cm, 24h GH profile -0.3+/-0.2ng/dl, peak GH -2.5+/-2.0ng/dl, IGF-I -202.4+/-72.4ng/dl, maximum oxygen peak -31.9+/-6.8L, maximum heart rate - 161.4+/-7.5 bpm and METs - 9.1+/-1.9. After regression analysis using the GH secretion profile (mean GH in 24h, spontaneous peak GH and basal IGF-I) as dependent variable, no correlations were found between these and the other evaluated parameters.