The effect of acute exercise on the cortisol awakening response

The effects of acute exercise on the cortisol awakening response (CAR), characterized by the rapid increase in cortisol concentrations within the 30-45 min following sleep offset has yet to be fully elucidated. Thus, our study investigated the effects of late-evening acute exercise on the CAR the following morning. We hypothesized that exercise would have a significant effect on the CAR the following morning. Twelve participants (mean (SD): age = 23 (4) years; mass = 76.8 (8.7) kg; height = 175.6 (5.0) cm; [Formula: see text]O2max = 48.9 (7.5) ml.kg^-1.min^-1) reported to the laboratory in the evening (1800 h) on two occasions and were randomly assigned to either exercise for one hour (70-75% of maximal power output) or rest condition. Blood and saliva samples were assayed for cortisol. Mixed-effects models determined the effect of exercise on the cortisol response post-waking in both blood and saliva. Participants demonstrated an average exercise-induced increase in circulating cortisol of 477.3%, with actual mean (SD) heart rate relative to maximum of 87.04% (6.14%). Model results demonstrated a negative effect for exercise condition when modeling the serum and salivary cortisol responses to awakening via a quadratic growth model (serum, β_Condition = - 42.26 [95% CI - 64.52 to - 20.01], p < 0.001; saliva, β_Condition = - 11.55 [95% CI - 15.52 to - 7.57], p < 0.001). These results suggest that cortisol concentrations in saliva and blood are significantly lower the morning following a prior evening exercise session. Therefore, the CAR may serve as a useful biomarker to monitor responses to exercise training, although the underlying mechanism for these decreases in the CAR should be investigated further.

Biological Markers of Training Level among Qualified Greco-Roman Wrestlers

BACKGROUND: The article presents the dynamics of biochemical indicators showing the tension of body functional systems in qualified Greco-Roman wrestlers at the pre-competition stage. Biochemical indicators can be regarded as the markers of training level, as a reflection of adaptive changes during performing training loads. AIM: The study aims to examine the adaptive reactions of body internal systems in wrestlers to the load performed at the stage of pre-competition training. METHODS: The methodological basis of the study is the examination of the reaction of body functional systems in wrestlers (n = 24) in response to the load performed at the stage of pre-competition training. The basis of the studied indicators of wrestlers’ organisms is the dynamics of the enzymatic activity (ALT and AST), the activity of creatine phosphokinase, and the balance of anabolic and catabolic processes in the course of a 2-week macrocycle of the pre-competition training. RESULTS: A high level of enzymatic activity (ALT and AST) was noted as the response to shock training load in the first and the second training macrocycles against the background of a negative trend during the entire sports event, which indicates a directed decrease in the heart’s tension muscle, being an indicator of adaptive changes occurring in wrestlers’ body energy. The high variability of AST indicators on the first day and creatine phosphokinase throughout the entire pre-competition training pointed out an individual level of adaptive reactions of the athletes’ bodies in response to the training load taken. CONCLUSIONS: The results of the study have shown notable dynamics in the indicators of the enzymatic activity of AST, creatine phosphokinase, and the hormone cortisol in a series of shock training loads, as the response to adaptive changes in body energy systems, the value of which should be considered during the pre-competition training.