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Study aim
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Study of exercise performance and responses of coagulation, fibrinolysis, hormonal and metabolic systems to caffeine consumption in the morning and evening
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Design
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Randomized, double-blind, crossover, placebo-controlled trial design, phase 3 on 120 subjects. The rand function of Excel was used for randomization.
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Settings and conduct
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Each participant will participate in 4 experiment sessions with 7 days intervals: 2 sessions in the morning and 2 sessions in the evening following the ingestion of caffeine or a placebo. Each session will include: HIE (4 sets of 100-meter sprints), resistance exercise (2 sets of 12 repetitions at 70% of1RM for chest press, lat pulldown, shoulder press, and leg press), 30 min of aerobic exercise (running on a treadmill at 70% of maximal oxygen consumption), and a Wingate anaerobic test at the end of the session. Blood samples will be collected before, immediately after, and 30 minutes after the completion of each session. This study will be conducted in a double-blind manner, meaning that the administration of the supplement or placebo will be carried out by an individual not involved in the study, and the researchers will remain unaware of the assignments until after statistical analysis is completed. All study procedures will be conducted in Turkey.
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Participants/Inclusion and exclusion criteria
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Inclusion criteria:
Don't smoke؛
Do not consume alcohol؛
Have not taken any sports supplements in the past 6 months؛
Do not have a habit of consuming caffeine؛
Do not suffer from cardiovascular and hematological diseases.
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Intervention groups
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Acute supplementation of caffeine (3 mg/kg) or placebo (200 mg cellulose) + one exercise session + in the morning (8-10) and evening (17-19) for all participants according to the crossover study design.
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Main outcome variables
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Von Willebrand factor;
VIII factor;
Fibrinogen;
Platelate;
PAI-1 activity;
tPA antigen;
tPA activity;
Testosterone;
Cortisol;
Anaerobic power.