The acute effect of commercial "energy drink" on hematological, biochemical and strength parameters induced by eccentric contractions
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BACKGROUND: Commercial energy drink usage is reported to be higher in athletes and adolescents. However, the impact of pre-exercise consumption of energy beverages on hematologic and biochemical responses and skeletal muscle contractile properties has not been fully elucidated. METHOD: Ten male subjects performed 50 maximal eccentric actions on an isokinetic dynamometer at 90 degrees/sec followed by two identical trials that were preceded by consuming either a placebo (P) or energy drink (ED) beverage. The test was repeated after 7-10 days while consuming the alternate beverage. Complete blood counts and chemistry profile was conducted before and immediately after exercise. RESULTS: Eccentric contractions resulted in an increased number of neutrophils (Neut) and decreased lymphocytes (Lymph), decreased eosinophils (EOS) and did not change basophil (BASO) levels in control. However, the BASO levels increased immediately after the exercise with P and ED beverage consumption. In contrast, P and ED beverage consumption had no effect on Neut, Lymph, MONO or EOS counts after exercise compared to pre-exercise values. Acute exercise increased creatinine kinase (CK) and decreased phosphorus (Pi) but did not have any effect on other blood chemistry parameters. The biochemical profile and eccentric muscle contractile properties were not significantly affected by any of the beverages. CONCLUSIONS: Consumption of pre-exercise energy drink does not have a favorable effect on immune blood cells induced in the acute eccentric exercise model.