The effect of neuromuscular electrical stimulation and strength exercises of different intensities on cognitive function and urinary BDNF levels

Objective: Previous studies showed that the positive effect of exercise on cognitive function, however, there is a lack of literature results on the effect and mechanism of different muscular exercise practices on various components of cognitive function. This study aimed to evaluate the effect of Neuromuscular Electrical Stimulation (NMES) and upper extremity strength exercises of three different intensities on cognitive function and urinary BDNF (brain-derived neutrophic factor) concentration. Method: A total of 44 licensed athletes over the age of 18 were included in the study. In the study, a total of 6 groups were formed as control (CG), sham (SG), NMES (NG), low- (LG), medium- (MG), and high-intensity strength exercise (HG). Exercise programs of different intensities were created individually using biceps curls, taking into account 1 maximum reps. NMES was administered over the biceps muscle and using the classical protocol. Resting muscle strength, cognitive function, urinary BDNF, and creatinine measurements were taken before the interventions, and all measurements were repeated after the 10th session. An extended Stroop test was used in the cognitive evaluation, and urine BDNF and creatinine levels were evaluated by using the ELISA kit. The results were presented as mean + SD, p<0.05 was determined as statistical significance level, pre-post test means were evaluated by t-test, comparison between groups by analysis of variance. Results: The text-color and word reaction time was shortened and the number of errors decreased in the low, medium, and high-intensity exercise groups at the end of the 10th session. Urinary BDNF levels increased in the NG, OG, and YG groups, but the BDNF/creatinine ratio increased in the NG and DG groups, while it decreased in the YG group. Conclusion: The results of this study revealed that low, medium, and high-intensity strength exercises improve cognitive function and that BDNF levels contribute to this effect. Key words: attention, athlete, exercise intensity, resistance training, memory