Eligible participants will be randomized to receive placebo or spironolactone (50 mg/d) for 90 days (Phase I). At the completion of Phase I, participants will undergo repeat end-point assessment followed by a 21-day drug washout period. Then, the 90 day crossover phase of the trial will occur (Phase II), in which participants randomized to placebo in Phase I will be treated with spironolactone (50 mg/d) in Phase II and vice versa. At the conclusion of Phase II, end-point measures are reassessed.