• DOI:10.1034/J.1399-3003.2000.01525.X
• Corpus ID: 6902092

Reference value of six-minute walking distance in healthy middle-aged and older subjects.

@article{Teramoto2000ReferenceVO,
  title={Reference value of six-minute walking distance in healthy middle-aged and older subjects.},
  author={Shinji Teramoto and Eijiro Ohga and Takeo Ishii and Y Yamaguchi and H Yamamoto and T Mastsuse},
  journal={The European respiratory journal},
  year={2000},
  volume={15 6},
  pages={
          1132-3
        }
}

• S. Teramoto, E. Ohga, +3 authors T. Mastsuse
• Published 1 June 2000
• Medicine
• The European respiratory journal

In a recent issue of the European Respiratory Journal, TROOSTERS et al. [1] carefully demonstrated that the six-minute walking distance (6MWD) can be predicted adequately using a clinically useful model in healthy elderly subjects. The 6MWD is a quick and inexpensive measure of physical function and an important component in assessing healthrelated quality of life (HRQoL). Although the maximal cycle ergometry or treadmill exercise test is a more accurate means of assessing HRQoL and physical function, these exercise tests cannot be performed in all elderly subjects. This is why the 6WMD is more useful for measuring the submaximal exercise capacity and quality of life in elderly, frail and severely limited patients. Several studies have indicated that the 6MWD is a good marker of response to therapeutic intervention in patients with chronic obstructive pulmonary disease [2±4]. To this end, an adequate reference value is necessary for assessing physical function in middle-aged and older subjects. The results of TROOSTERS et al. [1] are consistent with those of the several previous studies performed in various countries (table 1) [6]. However, reference equations for the 6MWD in healthy middle-aged and elderly subjects are not introduced for non-Caucasians. The experience of the present authors and the previous study in Japan [6] indicate that the reference value of the 6MWD in healthy elderly Japanese subjects is similar to that in elderly Caucasians (table 1). This evidence suggests that the normal value of the 6MWD at any given age may not be very different between Caucasians and non-Caucasians. We agree with TROOSTERS et al. [1] that a normal 6MWD should not be fixed at 600 or 700 m as has been previously proposed by REDELMEIER et al. [7]. However, TROOSTERS et al. [1] also found that the 6MWD correlated significantly with patients© ratings of their own walking ability and that the variability in repeated measurements of the 6MWD in patients with good baseline functional status was greater than that in patients with worse baseline functional status as measured by the 6MWD. This suggests that the interindividual variability in 6MWD in healthy elderly subjects is greater than that in severely limited patients with lung disease. Although TROOSTERS et al. [1] claimed no information was available as to which factors may account for variability in the measured 6MWD in healthy elderly subjects, the previous studies have revealed that age and sex are the most important factors explaining the variability [4, 6]. ENRIGHT and SHERRILL [5] reported that age, sex, weight and height are independently associated with the measured 6MWD using a larger sample size compared with the current one. Thus the result and conclusion of the current study are not surprising. In addition, a minor, but significant, point is that elderly subjects are considered to be subjects aged $65 yrs by geriatric standards. Data in subjects with a mean age of 65 yrs may not be representative of those in elderly subjects as a whole. It is true that the results of the 6MWD are interpreted more adequately if expressed as a percentage of the predicted value. Although the large variation in the 6MWD remains unexplained in terms of anthropometric parameters of age, weight, and height alone, the reference equations of the 6MWD should be simple for clinical usage. Future population-based studies would obviously be welcome to determine adequate reference equations for the narrow normal range of the 6MWD at a given age.