Gender impacts the post-exercise substrate and endocrine response in trained runners

Abstract

Background

Although several studies have investigated gender differences in the substrate and endocrine responses during and following endurance exercise, few have studied sex differences during a more prolonged recovery period post endurance exercise. The purpose of this study was to compare and characterize the endocrine and substrate profiles of trained male and female adult runners during the three-and-a-half hour recovery period from an endurance run.

Methods

After consuming a euenergetic diet (1.8 g·kg^-1·d^-1 protein, 26% fat, 58% carbohydrates, 42.8 ± 1.2 kcal/kg body weight) for 8 days, blood was collected from trained male (n = 6, 21 yrs, 70 kg, 180 cm, 9% body fat, VO_2peak 78.0 ± 3.4 mL·kg FFM^-1·min^-1) and female (n = 6, 23 y, 66 kg, 170 cm, 29% body fat, VO_2peak 71.6 ± 4.5 mL·kg FFM^-1·min^-1) endurance runners at rest and during recovery from a 75 min run at 70% VO_2peak. Circulating levels of glucose, lactate, free fatty acids (FFAs), insulin, cortisol, growth hormone (GH), and free insulin-like growth factor I (IGF-I) were measured.

Results

During the recovery period, females experienced increases in glucose, lactate and insulin while no changes were noted in men (P < 0.05). Males experienced increases in GH and decreases in IGF-I levels respectively (P < 0.05) while no changes were observed in females. FFA levels increased during recovery from endurance exercise, but changes were not different between genders.

Conclusion

These data further document gender differences in substrate and endocrine changes during a prolonged recovery period following endurance exercise. Future studies are needed to evaluate the effect of differing diets and nutritional supplements on these gender-specific post-exercise substrate and endocrine differences.

Keywords:

• Growth Hormone
• Endurance Exercise
• Growth Hormone Concentration
• Menstrual Cycle Phase
• Diagnostic System Laboratory

Electronic supplementary material

The online version of this article (doi:10.1186/1550-2783-5-7) contains supplementary material, which is available to authorized users.

Lisa M Vislocky, P Courtney Gaine, Matthew A Pikosky, William F Martin and Nancy R Rodriguez contributed equally to this work.

Copyright comment

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Electronic supplementary material

The online version of this article (doi:10.1186/1550-2783-5-7) contains supplementary material, which is available to authorized users.

Lisa M Vislocky, P Courtney Gaine, Matthew A Pikosky, William F Martin and Nancy R Rodriguez contributed equally to this work.

Copyright comment

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Acknowledgements

The authors are grateful to the runners who willingly participated in these investigations and for the efforts of Connie Cantor and all of the graduate students who helped make this project possible.

Competing interests

This study was supported in part by the National Cattlemen's Beef Association (NCBA), the Gatorade Sports Science Institute (GSSI), and the University of Connecticut Research Foundation. The results of the present study do not constitute endorsement of the NCBA or the GSSI by the authors or by ISSN.

Authors' contributions

LMV participated in the implementation of the study, assisted in carrying out the immunoassays, and drafted the manuscript. PCG conceived of the study, participated in its design and coordination, carried out the immunoassays, performed the statistical analyses, and helped draft the manuscript. MAP participated in the implementation of the study and assisted in carrying out the immunoassays. WFM participated in the implementation of the study and assisted in carrying out the immunoassays. NRR participated in the study design and helped draft the manuscript. All authors read and approved the final manuscript.