L. Heenan, H. Grimes, A. Olson, M. Ortiz, J. Sauter, C. Wutzke

Gonzaga University, Spokane, WA

Previous studies suggest cognitive loading yields cardiovascular repercussions, such as increases in heart rate, blood pressure, and muscle sympathetic nerve activity (MSNA). Increased MSNA may yield a net vasoconstrictor response, decreasing blood flow in active muscle during exercise. As blood flow is implicated in time to exhaustion (Tex) during resistance exercise, a MSNA-driven decrease in active hyperemia may result in decreased exercise sustainability. Response to a Stroop test is also variable, with positive and negative responders yielding differences in MSNA response to cognitive loading. Mood during extended exercise bouts have been correlated to Tex, indicating a potential cognitive aspect to performance. PURPOSE: To determine the physiological effects associated with cognitive loading and mood during resistance exercise performance. METHODS: Four males and seven females (mean ± SD; 21.00 ± 0.91 yr, 73.14 ± 23.21 kg, 170.31 ± 11.59 cm) completed two trials of leg extension exercise to failure at a duty cycle of 2 seconds of contraction to 1 second of relaxation while performing the Stroop test or a control, counterbalanced and separated by 48 hours. Surveys were used to measure mood. The rating of perceived exertion (RPE) was collected every minute during the trial, and Stroop and control interventions began after one minute of exercise. Heart rate (HR) was collected every 10 seconds. Electromyography (EMG) of the rectus femoris and vastus lateralis was measured during the trial. RESULTS: No difference in EMG values were found between the Stroop and control conditions at either 5% or 90% of test duration in either muscle. Mood before the Stroop and control exercise trials were the same (p > 0.05). During Stroop and control trials, no difference in HR (control Tex 130.00 ± 20.48; Stroop Tex 120.91 ± 15.58) or RPE (control Tex 19.09 ± 1.50; Stroop Tex19.27 ± 1.35) at any time point was observed. Tex was statistically similar between the Stroop (312.82 ± 135.24sec) and control (326.36 ± 153.07sec) conditions. CONCLUSION: Cognitive loading does not appear to shift Tex, which may indicate that the Stroop test yields differing cardiovascular effects between exercise and rest or that these effects are not of sufficient magnitude to reach tangible differences in exercise performance.

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