Seven-day intake of anthocyanins from New Zealand blackcurrant (NZBC) extract increased cardiac output and femoral artery diameter during a sustained submaximal isometric contraction. It is not known if there are intake duration effects by NZBC extract on the isometric contraction-induced cardiovascular responses. In a repeated measures design, male participants (n=19, age: 26±4 years) performed a 120-second submaximal (30%) isometric contraction of the knee extensors at baseline and following 1, 4 and 7-days intake of 600 mg·day-1 NZBC extract. During the 120-second submaximal isometric contraction, femoral artery diameter and cardiovascular responses were measured with ultrasound and beat-to-beat hemodynamic monitoring. Femoral artery was larger following 4-days (mean difference=0.046, 95% CI [0.012, 0.080 cm], p=0.005) and 7-days (mean difference=0.078, 95% CI [0.034, 0.123 cm], p<0.001) in comparison to baseline with no increase with 1-day intake. Systolic and diastolic blood pressure, heart rate and total peripheral resistance were not changed by NZBC extract at 1, 4 and 7-days intake. However, mean arterial pressure, stroke volume, cardiac output and total peripheral resistance were changed at time points during the isometric contraction following 7-days intake in comparison to 1-day intake of NZBC extract (p<0.05). Alterations in femoral artery diameter and some cardiovascular responses during a submaximal sustained isometric contraction of the knee extensors are affected by the intake duration of New Zealand blackcurrant extract, with no effects by 1-day intake. Our observations suggest that the bioavailability of blackcurrant anthocyanins and anthocyanin-derived metabolites is required for days to alter the mechanisms for isometric-contraction induced cardiovascular responses.