Carbohydrate and fatty acid metabolism responses to a graded maximal exercise test and recovery period in athletes and sedentary subjects

Abstract

Objective: Was to investigate glucose and free fatty acid (FFA) responses to a graded maximal exercise test and recovery period in athletes and sedentary subjects. Subjects and methods: Twelve trained man (TG) and twelve untrained men (UTG) performed an incremental maximal treadmill test. Blood samples were taken from all subjects in the morning before, at the end of the test and after 30 minutes of recovery. Insulin, glucose and FFA levels were determined at these points in time. Results: Glucose concentration did not differ between TG and UTG at rest. Glucose levels increased steadily during exercise in both groups, but this increase was significant only in UTG at the end of the exercise test (+18.71%; P < 0.05) and after 30 min of recovery (+12.05%; P < 0.05) compared to basal levels. FFA concentrations at rest were significantly higher in TG than UTG (P < 0.05). FFA concentration initially significantly decreased during exercise in TG (-50.00%; P < 0.05), and increased during recovery period, but stayed significantly lower than rest values (-25.00%; P < 0.05). In UTG, FFA levels insignificantly decreased (P > 0.05) during exercise and recovery period. Insulin concentration significantly increased during exercise in both groups (+23.89% in TG and +47.64% in UTG, P < 0.05), and stayed significantly higher in recovery period in UTG (+60.82%; P < 0.05). Conclusion: The data presented indicate that chronic physical training markedly influences serum FFA profile in trained group. Our findings also indicate that metabolic response to one bout of maximal-intensity exercise test depends on training status of the subjects and that trained subjects (athletes) could have higher substrate flexibility under high energy demand. © 2015 Elsevier Masson SAS.