Physicians who provide care for elderly patients need inexpensive tests to measure functional capabilities or limitations. The six-minute walk test is one way to evaluate these patients, and it can be performed by many frail and severely limited patients who would not tolerate cycle ergometry or treadmill exercise tests. A walking test in elderly patients is more reliable than timed chair stands or weight lifting. In addition, the distance of the six-minute walk has been shown to be reduced by conditions such as chronic obstructive lung disease, arthritis, cardiovascular disease, and neuromuscular disorders. Although the six-minute walk test has been studied in patients with specific diseases, no studies have assessed this test in elderly patients with multiple comorbidities. Enright and colleagues evaluated the six-minute walk test as a measure of functional status in elderly adults.
The study participants were Medicare-eligible adults in four communities in four states. These communities were diverse in proportions of minorities, education levels, income levels, degrees of urbanization, death rates, and availability of care. The initial cohort was recruited from 1989 through 1990, with an additional cohort enrolled between 1992 and 1993 to enhance the representation of the study. Participants had annual follow-up visits.
During the June 1996 through May 1997 evaluation, all patients who were not excluded from the study performed the six-minute walk test. Exclusion criteria included use of an ambulatory aid; inability to walk because of musculoskeletal problems; a resting oxygen saturation of less than 90 percent; chest pain within the past four weeks; a myocardial infarction, angioplasty, or heart surgery within the past three months; heart rate of less than 50 beats per minute or more than 110 beats per minute at rest; or acute ST-T wave changes on electrocardiography.
The six-minute walk test was performed using an internal hallway with a marked distance of 100 feet. Patients were instructed to walk the distance at their own pace but to cover as much ground as possible. They were allowed to stop and rest during the test if needed. Before and after the test, patients were asked to rate their dyspnea and whether they had experienced any dyspnea, chest pain, light-headedness, leg pain, or other symptoms at the end. In addition, patients were assessed for functional status, health status, depression symptoms, cardiovascular disease, and pulmonary function.
Of the 2,281 participants who performed the six-minute walk test, 2,117 were able to complete it. No adverse events occurred during the test, and approximately 75 percent of participants reported no symptoms at the end. The mean walking distance was 362 meters (1,188 feet) for men and 332 meters (1,089 feet) for women. Older age, higher weight, larger waist circumference, weaker grip strength, depression symptoms, and decreased mental status were general correlates for shorter walking distances during the test. Other variables associated with a shorter walking distance included impaired activities of daily living; self-reported poor health; less education; nonwhite race; and a history of coronary heart disease, transient ischemic attacks, stroke, or diabetes.
The authors conclude that most elderly persons can safely perform the six-minute walk test in the outpatient setting. The test can be used to assess the impact of multiple comorbidities on exercise capacity and functional capabilities in older adults. The authors add that expected values need to be adjusted for each patient's age, gender, height, and weight.
editor's note: Physicians who care for elderly patients should try to establish their functional status. When multiple medical illnesses are present, the capability of elderly patients to care for themselves may be compromised. Enright and colleagues demonstrated that one simple technique to assess elderly patients is the six-minute walk test. This test is safe, simple to perform, and can be done in the office with no equipment. Using this information, physicians can identify at-risk patients who perform poorly on this test and provide the appropriate interventions. Use of this test could lead to a safer environment for elderly patients who are at risk for further complications from their inability to perform basic tasks.—k.e.m.