Background The aim of our study was to determine whether the use of food supplement L-arginine improves vascular function, which could be beneficial in preventing the formation and development of cardiovascular diseases. We investigated differences between trained and sedentary subjects. Method Measurements were performed in healthy normotensive men, divided into four groups, according to age and physical activity: 12 young sedentary (YS) (mean age 23,5 ± 2,4) and age matched trained (YT) (N = 18); 11 elder sedentary (ES) (mean age 45,7 ± 7,5) and age matched trained (ET) (N = 12) subjects. Parameters were measured at rest with the Task Force Monitor device (CNSystems Medizintechnik, Austria) before and after administration of 0.9 g L-arginine. Results After ingestion of L-arginine the heart rate in all groups statistically significantly decreased (YS 70.4 ± 4.2 vs. 66.3 ± 3.3; YT 62.1 ± 2.7 vs. 58.3 ± 2.0; ES 69.6 ± 3.2 vs. 62.7 ± 2.7; ET 58.0 ± 1.8 vs. 53.6 ± 1.2 beats/ min) (paired t-test, p < 0.05). The cardiac output decreased in three groups (YT 7.04 ± 0.4 vs. 6.32 ± 0.3; ES 6.95 ± 0.5 vs. 5.9 ± 0.4; ET 7.08 ± 0.6 vs. 6.58 ± 0.4 L/min) (paired t-test, p < 0.05). The systolic (126.3 ± 4.1 vs. 120.0 ± 3.2 mmHg) and diastolic pressure (77.6 ± 2.5 vs. 74.3 ± 1.9 mmHg) (paired t-test, p < 0.05) decreased in the ES group. Conclusions The systemic effect of L-arginine was observed. Improved cardiovascular function in response to L-arginine could justify the use of dietary L-arginine supplementation.