Abstract
PURPOSE: This study was designed to investigate whether a liquid carbohydrate (CHO) consumed before, during, and immediately after a bout of resistance exercise would influence the plasma concentrations of three hormones that affect protein balance: insulin, insulin-like growth factor-1 (IGF-1), and cortisol. METHODS: Twenty males [X(SD), age = 20±0.4 years, BMI = 24.8±0.7 kg/m2] completed in random order three separate treatment conditions: 1) ExCHO: strenuous 80-min. resistance exercise while consuming a 6% carbohydrate beverage at regular intervals based on body size (X=77g CHO, 310 kcal); 2) ExPLA: same exercise as EXCHO but with non-caloric placebo; and 3) NoExCHO: no exercise trial of quiet sitting and the same CHO consumption as ExCHO. Blood samples were obtained before, during, immediately post exercise, and 90 min after exercise and were analyzed for concentrations of the three hormones. RESULTS: Plasma insulin concentrations were significantly higher during and immediately following ExCHO compared to ExPLA, but were not different 90 minutes post-exercise. (During: ExCHO= 11.1 uU/ml; ExPLA = 7.3 uU/ml) (Immediately following; ExCHO = 16.2 uU/ml; ExPLA = 7.3uU/ml). IGF-1 concentrations increased over time across the three conditions, but were not affected by CHO consumption (P>0.05). Plasma cortisol was higher before, during, and immediately after exercise for the ExCHO (16.1, 15.9, 18.0 ug/dl) and ExPLA (16.0, 16.1, 19.2 ug/dl) conditions compared to the same time points for NoExCHO (14, 11.5, 11.5 ug/dl). However, plasma [cortisol] did not differ at any time point between ExCHO and ExPLA. At 90 minutes post-exercise, plasma [cortisol] decreased significantly for EXCHO (12.8 ug/dl) and ExPLA (13.0 ug/dl), with values not different from NoExCHO (11.6 ug/dl). CONCLUSIONS: During resistance exercise, plasma [insulin] was higher with CHO consumption than without, but plasma [cortisol] and [IGF-1] were not affected by CHO consumption during resistance exercise. Whether such changes in systemic insulin favor postive protein balance in this contex remains to be seen.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
