Activity level predicts 6-minute walk distance in healthy older females: an observational study

BackgroundThe 6-minute walk test (6MWT) is widely used in clinical practice and research. Few studies have investigated activity level as a predictor of 6-minute walk distance (6MWD), and existing predictive models do not allow for activity level.ObjectivesTo evaluate if knowledge of the level of physical activity enhanced the ability to predict 6MWD, and if the inclusion of activity level added to the predictive accuracy of existing models for the 6MWT in healthy older women; and to validate existent predictive models for 6MWD in a new sample.DesignCross-sectional, observational study.SettingFour elderly communities.ParticipantsA convenience sample of healthy active and sedentary older non-smoking females with no musculoskeletal or lung disorders.Main outcome measuresAge, height, weight, spirometric values and 6MWD.ResultsSeventy-seven out of 154 females met the inclusion criteria [mean age 66 (standard deviation 6.5) years]: 46 were active and composed the active group and 31 were sedentary and composed the sedentary group. The active group had significantly greater 6MWD than the sedentary group (mean 44 m; 95% confidence interval 14 to 73 m; P < 0.01). Previous published models that did not allow for activity level either over or underestimated the 6MWD in this sample. The activity level was shown to be an important independent predictor of 6MWD.ConclusionThis study demonstrates the importance of considering the level of physical activity when predicting 6MWD in older women.