Some studies9,10 have shown good test-retest reliability for measurements obtained with the 6MW in patients with cardiovascular disease, with intraclass correlation coefficients (ICCs [model not stated]) from .94 (61 men, 3 women; mean age=68 years, SD=7, range=45– 88)10 to .96 (40 men, 5 women; mean age=49 years, SD=8).6