Growth hormone pulsatility profile characteristics following acute heavy resistance exercise

Bradley C. Nindl, Wesley C. Hymer, Daniel R. Deaver, William J. Kraemer


This investigation examined the hypothesis that acute heavy resistance exercise (AHRE) would increase overnight concentrations of circulating human growth hormone (hGH). Ten men (22 ± 1 yr, 177 ± 2 cm, 79 ± 3 kg, 11 ± 1% body fat) underwent two overnight blood draws sampled every 10 min from 1700 to 0600: a control and an AHRE condition. The AHRE was conducted from 1500 to 1700 and was a high-volume, multiset exercise bout. Three different immunoassays measured hGH concentrations: the Nichols immunoradiometric assay (Nichols IRMA), National Institute of Diabetes and Digestive and Kidney Diseases radioimmunoassay (NIDDK RIA), and the Diagnostic Systems Laboratory immunofunctional assay (DSL IFA). The Pulsar peak detection system was used to evaluate the pulsatility profile characteristics of hGH. Maximum hGH was lower in the exercise (10.7 μg/l) vs. the control (15.4 μg/l) condition. Mean pulse amplitude was lower in the exercise vs. control condition when measured by the Nichols IRMA and the DSL IFA. A differential pattern of release was also observed after exercise in which hGH was lower in the first half of sleep but higher in the second half. We conclude that AHRE does influence the temporal pattern of overnight hGH pulsatility. Additionally, because of the unique molecular basis of the DSL IFA, this influence does have biological relevance because functionally intact molecules are affected.

  • immunofunctional assay
  • somatotropin
  • strength training


  • This study was supported, in part, by NIH Grant MO1-RR-10732 and grants received from the American College of Sports Medicine and the National Strength and Conditioning Association (to B. C. Nindl).

  • Address for reprint requests and other correspondence: B. C. Nindl, Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760 (E-mail:bradley.nindl{at}

  • The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

View Full Text