In this issue of CHEST (see page 387), Enright et al report on their multicenter study, which involved 2,281 individuals, aged ≥ 68 years. This sample was selected from a larger cohort of 5,201 participants who were initially recruited and examined. Exclusion criteria for the study were institutionalization, terminal illness, inability to walk, and communication disorders. The test was considered to be safe, since no untoward effects were reported, with no need for an emergency intervention. From this initial group, about one third of patients were excluded from the walking test because of generally poor health. The remaining subset of healthy patients was used to construct prediction equations. The healthy men covered an average walking distance of 400 m (95% confidence interval, 280 to 533 m), and the healthy women walked 367 m (95% confidence interval, 249 to 479 m) during a 6-min walking period.