Black individuals have lower plasma natriuretic peptide (NP) concentrations than white individuals. However, race-based differences in the NP response to physiological perturbations are unknown. In this physiological trial (NCT#03070184), we measured the NP [mid-regional atrial NP (MR-proANP), N-terminal pro-B-type NP (NT-proBNP), and BNP] response to physiological perturbations among healthy, self-identified Black and white participants aged 18-40 years. The primary and secondary outcomes were the change in plasma NP concentrations at 6 weeks after metoprolol (initiated at 50 mg/day and doubled every 2 weeks) and standardized, aerobic exercise (70% of their maximal oxygen uptake on a salt-standardized background), respectively. Among 40 Black [median age: 27 (22, 32) years
21 (52.5%) women] and 40 white [median age: 25 (20, 30) years
19 (47.5%) women] participants, exercise increased MR-proANP (Black: 35%
white: 43%), NT-proBNP (Black: 11%
white: 23%), and BNP (Black: 59%
white: 61%) in both self-reported races. Exercise was associated with an increase in plasma MR-proANP (p