Abstract OBJECTIVES The aim of this study was to explore the full range of tricuspid valve regurgitation velocity (TRV) at rest and with exercise in disease free individuals. Additionally we examined the relationship of stroke volume (SV), cardiac output (CO) and TRV to exercise capacity. BACKGROUND Doppler evaluation of TRV can be used to estimate pulmonary artery systolic pressure (PASP). Most studies have assumed TRV ≤2.5 m/s as the upper limits of normal. The full range of TRV with exercise has been incompletely defined. METHODS Highly conditioned athletes (n = 26) and healthy, active, young male volunteers (n = 14) underwent standardized recumbent bicycle exercise. Exercise parameters included: TRV, SV, CO, systolic (SBP) and diastolic (DBP) systemic blood pressure. RESULTS Tricuspid valve regurgitation, SV, HR and CO were significantly higher in athletes than in nonathletes over all workloads, including rest. Systolic blood pressure and DBP did not show significant differences between the two groups. CONCLUSIONS This study defines the upper physiologic limits of TRV at rest and during exercise in normals and provides a noninvasive standard for the diagnosis of pulmonary hypertension.