Over the past five years, the popularity of dietary nitrates as an ergogenic device among athletes has increased significantly. Hypoxic and acidic conditions that occur during exercise facilitate the conversion of nitrite to nitric oxide (NO) and increase the physiological efficiency of exogenously produced nitrite. After a few years of our team predicted experiments, as a nitric oxide precursor, amaranth (Amaranthus hypochondriacus) was identified as a source of dietary nitrates (concentrations 9-11%). The aim of this study was to evaluate the effect of single-dose and long- term doses of dietary nitrates from amaranth concentrate on the aerobic capacity of physically active young persons. Thirteen healthy and physically active young participants were randomized to experimental and placebo groups using a increasing cycling exercise (ICE) and placebo- controlled design. Pulmonary gas exchange recording (oxygen uptake (VO 2 ), pulmonary ventilation (VE), respiratory exchange ratio (RER)) and analysis of blood lactate samples were obtained. Our findings indicate that the single dose of dietary amaranth (400 mg) significantly improved only the power of the test performance. Long-term (6 days) intake significantly increased the power of the test performance, the maximum oxygen consumption and the power of the test for the first ventilation threshold value (from 37.7±2.7 mL/kg/min during the first test to 41.2±5.4 mL/kg/min during the third test, p <0.05).