RESUMO
After menopause the incidence of cardiovascular diseases increases in women. A decrease in nitric oxide (NO) bioavailability has been pointed out to play a major role in this phenomenon. Since it is believed that l-arginine administration could improve NO bioavailability, the aim of this study was to examine the effects of acute l-arginine administration associated with aerobic exercise on blood pressure (BP), redox state and inflammatory biomarkers in normotensive postmenopausal women (NPW). Sixteen volunteers (57±6yr) were subjected to four experimental sessions (crossover design): arginine+exercise (A-E); arginine (ARG); exercise+placebo (EXE); control (CON). Each session was initiated with either 9g of l-arginine ingestion (ARG or A-E days), placebo (EXE day), or nothing (CON day). The participants performed 30min of aerobic exercise (A-E and EXE days) or sitting rest (CON and ARG days). Blood samples were collected before each session and 45min after the intervention. Office BP and ambulatory blood pressure monitoring (ABPM) were evaluated. NO/cGMP pathway, redox state and inflammatory biomarkers were measured. Systolic BP decreased during the 24-hour in A-E and EXE sessions. However, diastolic BP reduced only in A-E session. No changes were found in the biomarkers concentrations. In conclusion, the association was effective in lowering diastolic BP in NPW. Additionally, physical exercise alone promoted a long lasting effect on systolic BP measured by ABPM in this population, although this beneficial effect was not associated with changes in the cardio-inflammatory biomarkers. Possibly, other factors such as neural influences could be mediating this effect.