Chest
Clinical InvestigationsEXERCISE6-Minute Walk Work for Assessment of Functional Capacity in Patients With COPD
Section snippets
Study Population
One hundred twenty-four patients (90 men and 34 women) between 45 and 81 years of age with moderate-to-very severe COPD participated in this clinical trial. This trial was approved by the local institutional review board. All patients were initially screened for study eligibility by a pulmonary physician. All participants met the following entry criteria: (1) FEV1 35 to 70% of predicted, FEV1/FVC ratio 30 to 60%, and a total lung capacity of > 90% of predicted; (2) capable of undergoing
Results
All 90 men and 34 women completed the 6MW test and cycle ergometry with gas exchange. Men were slightly taller and heavier than women (Table 1). Both men and women had extensive smoking histories, with men reporting a significantly greater number of pack-years of smoking (66 pack-years) than women (48 pack-years; p < .01). As presented in Table 2, disease severity ranged from moderate to severe airway obstruction, as determined by their pulmonary function indexes. Women presented with a
Discussion
Our findings indicate an advantage for using the calculation of work over simple distance covered in 6-min of level walking for patients with COPD (correlational analysis with less scatter observed and ROC analysis). The work calculation takes into account the mass of the body and the energy required to move that body through space. Since all individuals vary with respect to body weight, the expected work of walking/ambulation will vary. By including the work calculation for the 6MW, a major
Summary
We have demonstrated that the product of body weight × distance or work is a good measure for reporting exercise capacity for the 6MW test for patients with COPD. This work calculation yields improved correlation coefficients with lung function and gas exchange indexes in the patients studied. Through ROC analysis, the area under the curve was significantly greater for 6MWORK compared to 6MWD. This suggests greater sensitivity and specificity for 6MWORK. Thus, the work calculation appears to be
References (35)
- et al.
The body weight-walking distance product as related to lung function, anaerobic threshold and peak VO2 in COPD patients
Respir Med
(2001) - et al.
The Veterans Administration Army Cooperative Study of Pulmonary Function: the lung volume and its subdivisions in normal men
Am J Med
(1966) - et al.
Single breath diffusing capacity in the industrial setting
Chest
(1982) - et al.
Predicting maximal exercise ventilation in patients with chronic obstructive pulmonary disease
Chest
(1987) Basic principles of ROC analysis
Semin Nucl Med
(1978)- et al.
Differing effects of airway obstruction on physical work capacity and ventilation in men and women with COPD
Chest
(1994) Breathlessness in patients with chronic airflow limitation: mechanisms and management
Chest
(1994)- et al.
The relationship of the 6-min walk test to maximal oxygen consumption in transplant candidates with end-stage lung disease
Chest
(1995) - et al.
Twelve minute walking tests for assessing disability in chronic bronchitis
BMJ
(1976) - et al.
The 6-minute walk: a new measure of exercise capacity in patients with chronic heart failure
Can Med Assoc J
(1985)
Two, six and 12-minute walk tests in respiratory disease
BMJ
Validity and reliability of the 6-minute walk test in a cardiac rehabilitation population
J Cardiopulm Rehabil
The 6-minute walk: a simple test with clinical application
Eur Heart J
Reference values for a multiple repetition 6-minute walk test in healthy adults older than 20 years
J Cardiopulm Rehabil
Reference equations for the six-minute walk in healthy adults
Am J Respir Crit Care Med
External work in walking
J Appl Physiol
A theoretical and experimental analysis of anemities in the estimation of pulmonary diffusing capacity by single-breath holding method
Q J Exp Physiol
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Estimating maximum work rate during cardiopulmonary exercise testing from the six-minute walk distance in patients with heart failure
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2022, Science and SportsCitation Excerpt :Alternative indices derived from the 6MWT have been assessed in other respiratory diseases and have shown their usefulness in evaluating exercise capacity [13–15]. The 6-min walk work (6MWW) index has exhibited higher correlation coefficients than the 6MWD when correlated with FEV1 in chronic obstructive pulmonary disease (COPD) [13]. In idiopathic pulmonary fibrosis, Lettieri et al. [15] reported that the distance-saturation product (DSP) predicted 12-month survival better than FEV1 and forced vital capacity (FVC).
This project was supported by grant No. R01 HS08774 from the Agency for Health Care Research and Quality.