D. Sharp, P. Kinder-Pyle, C. Rivas-Parra, C. Burress, C. Brewer

Eastern Washington University, Cheney, WA

‘Pre-workout’ refers to a variety of substances that are purported to enhance energy and extend exercise duration when taken prior to exercise. However, there is little research investigating the effects of pre-workout on hemodynamic responses during exercise. PURPOSE: To determine the effects of a pre-workout supplement (PWS) on heart rate (HR) and blood pressures (systolic SBP, diastolic DBP) responses to upper body resistance exercise. METHODS: College-aged males and females (n=6) completed a familiarization session followed by 2 resistance training workouts: control (PWS-) and treatment (PWS+) trials. The PWS contained 200mg caffeine, 2.75g arginine and agmatine, and 1.6g β-alanine and was consumed 20 minutes prior to exercise. The upper-body resistance routine was aligned with ACSM recommendations and consisted of 2 sets of bench press, row, band chest press, triceps dips, medicine ball curls, and medicine ball slams and throws. HR was measured manually and BP was measured with a digital cuff prior to, during and immediately after exercise, as well as after 6-minute passive recovery. Data were analyzed using a within-subjects repeated measures ANOVA with an alpha level set at 0.05. RESULTS: PWS had no significant effect on pre-exercise HR (PWS- 74 ± 11bpm; PWS+ 76 +7bpm, p=0.571), SBP (PWS- = 118 ± 3 mmHg; PWS+ = 126 ± 15 mmHg, p= 0.236), or DBP (PWS- 75 ± 7 mmHg; PWS+ 78 ± 5 mmHg, p= 0.206). PWS had no significant effect on exercise HR (PWS- 101±19 bpm; PWS+ 94±11 bpm, p=0.41), SBP (PWS- 131±6 mmHg; PWS+ 114±17 mmHg, p=0.71), or DBP (PWS- 78±7 mmHg; PWS+ 74±6 mmHg, p=0.23). PWS had no effect on recovery HR (PWS- 82±12 bpm; PWS+ 85±10 bpm, p= 0.55), SBP (PWS- 119±4 mmHg; PWS+ 128±12 mmHg, p= 0.08), or DBP (PWS- 77±6 mmHg; PWS+ 76±10 mmHg, p=0.91). CONCLUSION: Results suggests that PWS had no significant effect on HR or BP prior to, during, or immediately after exercise. Despite this, participants reported experiencing side effects of PWS including facial numbness, jitteriness, and perceived sensation of increased HR after ingesting the supplement. Future research should compare multiple brands of PWS and explore the effects of separate ingredients in PWS, such as arginine and agmatine. In light of reported side effects, future research should further explore the perceived effect of PWS on participants.

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