Exhaustive Resistance Exercise Alters Serum Creatine and Guanidinoacetic Acid in Active Men

Abstract

Exhaustive exercise adversely affects biomarkers of creatine metabolism yet it remains unknown when the values back toward pre-disturbance conditions. PURPOSE: To evaluate a 24-hour post-exercise response in serum guanidinoacetic acid (GAA), creatine and creatinine in young active men subjected to a single session of exhaustive resistance exercise and matched it with exercise-induced changes in serum cortisol, interleukin 6 (IL-6), creatine kinase (CK), and lactate dehydrogenase (LDH). METHODS: Twelve healthy active men (age 22.7 ± 0.8 years; weight 79.8 ± 7.3 kg; height 182.4 ± 4.9 cm; weekly exercise 5.1 ± 1.6 hours) were subjected to a single session of bench press exercise until volitional exhaustion, with venous blood sampled before, immediately after exercise (~2 min), and after 15 min, 60 min and 24 h after the end of exercise. RESULTS: Baseline values for serum GAA, creatine and creatinine were 2.2 ± 0.5 μmol/L, 18.9 ± 3.6 μmol/L, and 72.4 ± 6.0 μmol/L, respectively. Serum GAA significantly dropped for 9.6 ± 7.3% immediately after bench press exercise (95% CI, 5.0 to 14.2; P < 0.001), while both creatine and creatinine increased immediately after the test for 5.0 ± 2.5% (95% CI, 3.4 to 6.6; P < 0.001) and 11.9 ± 4.3% (95% CI, 9.2 to 14.6; P < 0.001), respectively. GAA and creatine levels recovered to the baseline values after 24 hours post-exercise, yet creatinine remained significantly higher at 24-hour period as compared to the baseline values for 2.5 ± 2.3% (95% CI, 1.0 to 4.0; P = 0.002). CONCLUSIONS: A single session of exhaustive resistance exercise induces transient alterations in biomarkers of creatine metabolism, with serum creatinine outlined as a most persistent marker of exhaustion. Exercise-induced changes in creatine metabolism poorly corresponded to perturbations in inflammation and muscle fatigue biomarkers following exercise. This project was partly supported by the Serbian Ministry of Education, Science and Technological Development (175037 and 179011), the Provincial Secretariat for Higher Education and Scientific Research (142-451-2473 and 114-451-710) and the Faculty of Sport and Physical Education, University of Novi Sad (2018 Annual Award).