Dynamics of GH secretion during incremental exercise in obesity, before and after a short period of training at different work-loads

Summary Background Growth hormone (GH) secretion is normally sensitive to physical exercise. Intensity and duration of exercise, fitness and age can all influence the GH response to exercise. In obesity, GH secretion is decreased both in basal conditions and in response to exercise. Objective To analyse the dynamics of GH response to a progressive cycloergometric test, conducted up to exhaustion, in adult normal subjects and obese patients, after a reconditioning program at different workloads. Design and methods We studied eight lean subjects (four men, mean age 34·3 years, range 26–47 years, mean body mass index (BMI) 22·1 kg/m2). GH was sampled at baseline and during the last 30 s of each power output increase. Anaerobic threshold (AT) was detected by the V‐slope method. The same test was carried out in 16 obese subjects (seven men, mean age 39·1 years, range 20–59 years, mean BMI 35·8 kg/m2) and repeated after a 4‐week reconditioning program consisting of aerobic workout (Group A, eight subjects, three men, mean age 40·5 years, range 22–59 years, mean BMI 33·6 kg/m2), and aerobic plus anaerobic work (group B, eight subjects, four men, mean age 37·6 years, range 20–56 years, mean BMI 38·0 kg/m2) for 6 days/week, with no dietary restrictions. Results Mean exercise peak occurred at higher intensity in controls (140 vs 110 W, P