Effects of PDE5 inhibitors (Viagra) on exercise blood pressure

Abstract

Introduction: Phosphodiesterase inhibitors (PDE5-i) (e.g. Viagra) inhibit the destruction of nitric oxide, and contribute to vasodilation, both in target tissues and generally. In the setting of heavy exercise, this may lead to a reduction in systemic vascular resistance and a decrease in blood pressure. Purpose: To evaluate the effect of PDE5-i on blood pressure responses during heavy exercise. Design: Controlled laboratory investigation. Methods: Well-trained, middle aged men completed 40 min exercise bouts beginning one hour after ingestion of a (double blind randomly ordered) PDE5- i (Viagra 50mg) or placebo. Blood pressure was measured at rest prior to exercise, throughout the exercise bout, and during the cool-down. Results: There was a significant reduction in Systolic blood pressure throughout the course of exercise. SBP at 0, 3 (warm-up), 15, 25, 35, 45 and 47 (cool-down) min on PDE5-i vs. control was 116 vs. 109, 129 vs. 122, 162 vs. 152, 166 vs. 152, 167 vs. 148, 166 vs. 154 and 142 vs. 134. Diastolic blood pressure was also significantly lower at each time period. Conclusions: Exercise after taking a PDE5-i reduces systolic blood pressure significantly throughout the exercise bout, but not to levels associated with hemodynamic compromise.