The six-minute walk test in community dwelling elderly: influence of health status

Abstract

Background: The 6 minutes walk test (6MWT) is a useful assessment instrument for the exercise capacity of elderly persons. The impact of the health status on the 6MWT-distance in elderly, however, remains unclear, reducing its value in clinical settings. The objective of this study was to investigate to what extent the 6MWT-distance in community dwelling elderly is determined by health conditions.

Methods: One hundred and fifty-six community dwelling elderly people (53 male, 103 female) were assessed for health status and performed the 6MWT. After clinical evaluation, electrocardiography and laboratory examination participants were categorized into a stratified six-level classification system according to their health status, going from A (completely healthy) to D (signs of active disease at the moment of examination).

Results: The mean 6MWT-distance was 603 m (SD = 178). The 6MWT-distance decreased significantly with increasing age (ANOVA p = 0.0001) and with worsening health status (ANCOVA, corrected for age p < 0.001).A multiple linear regression model with health status, age and gender as independent variables explained 31% of the 6MWT-distance variability. Anthropometrical measures (stature, weight and BMI) did not significantly improve the prediction model. A significant relationship between 6MWT-distance and stature was only present in category A (completely healthy).

Conclusions: Significant differences in 6MWT-distance are observed according to health status in community-dwelling elderly persons. The proposed health categorizing system for elderly people is able to distinguish persons with lower physical exercise capacity and can be useful when advising physical trainers for seniors.

Figure 1

Impact of Health Status on 6-Minute Walk Distance in Community Dwelling Elderly. ■ Male Participants N = 53. Female Participants N = 102. Bars represent mean values ± SE. Significant decrease of 6 Minutes Walk Distance with worsening health category (ANCOVA corrected for age p < 0.01). * Significantly higher 6 MWT-distance than categories B2and C (Bonferroni post-hoc test p < 0.01) ^†Significantly higher 6 MWT-distance than category C (Bonferroni post-hoc test p < 0.05).

Figure 2

Impact of Age on 6-Minute Walk Distance in Community Dwelling Elderly. ■ Male Participants N = 53. Female Participants N = 102. Bars represent mean values ± SE. Significant decrease of 6 Minutes Walk (6 MWT) Distance with increasing age category (ANOVA p < 0.01). * Significantly higher 6 MWT-distance than categories 65–69 and 75+ (Bonferroni post-hoc test p < 0.05 and p < 0.01 respectively). Significantly higher 6 MWT-distance than category 75+ (Bonferroni post-hoc test p < 0.01). ^‡Significantly higher 6 MWT-distance than category 75+ (Bonferroni post-hoc test p < 0.05).

Figure 3

Predicted and Actual 6-Minute Walk Distance in Community Dwelling Elderly. The bullets represent individual values according to the attributed health category: Green bullets Health Category A, Yellow bullets Health Category B1, Red bullets Health Category B2 and Black bullets Health Category C. The lines represent the fit line and the 95% confidence interval. The predicted values are based upon the proposed multiple linear regression model 6MWT-distance predicted (m) = 1192 - (6 × age) - (57 × health category) -(69 × gender) with age expressed in years; 0 for male and 1 for female; 1 for health-category A, 2 for health-category B1, 3 for health-category B2, 4 for health-category C. The standard error of the estimate is 147 m.