PURPOSE: The Six-minute walk test (6MWT) is a popular and widely accepted modality of objective evaluation of functional exercise capacity, as it is inexpensive and simple to perform. In 2002 American Thoracic Society (ATS) published guidelines for the 6MWT and recommended investigators to publish reference equations for healthy persons. Recent studies have established regression equations to predict the Six-minute walk distance (6MWD) in healthy Caucasians; however, regression equations have yet to be established for other populations.
METHODS: ATS standardized 6MWT method was used. Age, height, weight, and sex independently affect the 6MWD in healthy adults; therefore, these factors along with race were taken into consideration. Subjects were interviewed about medical history and medication use. A brief physical examination, pulse oximetry, dyspnea and fatigue scores were recorded before and after the 6MWT. The study is ongoing and enrollment would continue through summer. At present eighty healthy subjects have completed the test.
RESULTS: Fifty-five males and twenty-five females performed the test. The average age of the subjects was 36years (range 20-62years). The average height, weight and body mass index of males were 68.2inches, 175.3lbs and 26.1; and that of females were 63.5inches, 152.8lbs and 27.7 respectively. There were 38(47%) Asians, 20(25%) African-Americans, 10(13%) Hispanics, 8(10%) Caucasians and 4(5%) Middle-East subjects. The average 6MWD was 1513ft (range 980-1980ft). Males walked marginally more than females. Asian males walked less than their female counterparts. Among males Asians and African-Americans walked less than Caucasians and Hispanics. Among females Asians and Caucasians covered more distance than African-Americans and Hispanics.
CONCLUSION: The 6MWD (1513ft) in our study was much less as compared to the earlier studies (1837-2290ft). Although differences in age, height, weight and sex could explain some of this difference but racial characteristics of our study population may have led to decrease in 6MWD. This would be determined later by multivariate analysis after collection of final data.
CLINICAL IMPLICATIONS: Published equations for 6MWD derived from Caucasian subjects may not be accurate for other population groups.
DISCLOSURE: Rakesh Sinha, No Financial Disclosure Information; No Product/Research Disclosure Information