Clinical utility of cycle exercise for the physiologic assessment of growth hormone release in children.

The clinical utility of exercise as a stimulus for the physiologic assessment of growth hormone (GH) deficiency was examined in healthy children. In response to exercise tests performed on different days, serum GH concentrations exceeded 7 micrograms/L on both days in 9 of 10 children. Although there is variation in this method of physiologic testing in the response of serum GH concentration (significant mean differences in GH peak values, 27.1 vs 19.8 micrograms/L for the two tests), the exercise test proved clinically valid in that diagnostic levels of GH were exceeded on both days 90% of the time. We conclude that this exercise evaluation protocol has clinical utility for the assessment of GH deficiency in children.