Walking Ability is an Important Predictor of CV Disease and Mortality in the Elderly
Special Report
By Harold L. Karpman, MD, FACC, FACP, Clinical Professor of Medicine, UCLA School of Medicine. Dr. Karpman reports no financial relationship to this field of study.
Exercise capacity and fitness measurements have been successfully used to predict cardiovascular and total mortality in middle-aged adults.1-4 Extended walking tests have been of value when assessing exercise capacity in patients with chronic obstructive pulmonary disease, advanced heart failure, respiratory disease and/or osteoarthritis.5-8 A long-distance corridor walk test which is similar to the 6-minute walk test has previously been used to measure fitness in healthy older adults9 and has been demonstrated to predict mortality in patients with congestive heart failure.10
Newman and her colleagues from the National Institute on Aging hypothesized that analysis of the performance time and determination of the cardiovascular response to the exercise effort in patients who were able to complete the 400-m component of the long-distance corridor or walk test would successfully predict mortality, cardiovascular disease, mobility limitation and disability in a cohort of well-functioning adults in the eighth decade of life.11 The participants received standard instructions (ie, walk as quickly as you can without running at a pace that you can maintain) to walk 400 meters in a hallway in 20-m segments after a 2-minute warm up. After adjusting for potential confounders, those in the poorest quartile of functional capacity (ie, walk time greater than 362 seconds) had a significantly higher risk of death than those in the best quartile (ie, walk time less than 290 seconds).
Commentary
The use of the timed 400-m walking test to objectively demonstrate the ability to perform a measured amount of exercise in community-dwelling older adults without known difficulty in performing mobility-related tasks permitted the authors to discriminate mortality and cardiovascular risk and risk for mobility limitation and disability in this group of participants. Among the individuals who completed the walk, those who walked faster were found to be slightly younger, more often were men of the Caucasian race, were less likely to have significant health conditions, subclinical disease or cardiovascular risk factors, had lower body mass indices, and were more physically active. The findings in this extremely objective study11 involving 3075 adults between the ages of 70-79 confirmed well-established, published evidence that middle-aged men and women adults who are physically fit have a lower incidence of cardiovascular events and total mortality.1-3
At least one previous study has demonstrated that poor lower-extremity performance is strongly predictive of future disability, hospitalization and mortality.12 However, it should be recognized that the impact of any mobility-related deficits is significantly diminished or eliminated if the participant is able to successfully perform the timed 400-m "corridor" walk. The Newman study11 provides validation of the importance of having the capacity to walk longer distances and shows that there can be a wide range of exercise performance in well-functioning older adults. Therefore, besides being an important objective method for assessing the risk of total mortality, cardiovascular disease, mobility limitation and mobility disability in older individuals, it may be a superb technique which allows easy identification of patients afflicted with an early decline in overall function. In conclusion, this standardized exercise study has once again demonstrated the importance of physical fitness in reducing both mortality and incident cardiovascular disease.
References
1. Gulati M, et al. The prognostic value of a nomogram for exercise capacity and women N Engl J Med. 2005;353:468-475.
2. Mora S, et al. Ability of exercise testing to predict cardiovascular and all-cause death in asymptomatic women: a 20-year follow-up of the lipid research clinics prevalence study. JAMA. 2003;290:1600-1607.
3. Blair SN, et al. Physical fitness and all-cause mortality. A prospective study of healthy men and women. JAMA. 1989;262:2395-2401.
4. Myers J, et al. Exercise capacity and mortality among men referred for exercise testing. N Engl J Med. 2002;346:793-801.
5. Swerts PM, et al. Comparison of corridor and treadmill walking in patients with severe chronic obstructive pulmonary disease. Phys Ther. 1990;70:439-442.
6. Lucas C, et al. The 6-min walk and peak oxygen consumption in advanced heart failure: aerobic capacity and survival. Am Heart J. 1999;138(4 Pt 1):618-624.
7. Butland RJ, et al. Two-, six-, and 12-minute walking tests in respiratory disease. Br Med J (Clin Res Ed). 1982;284:1607-1608.
8. Peloquin L, et al. Reliability and validity of the five-minute walking field test for estimating VO2 peak in elderly subjects with knee osteoarthritis. J Aging Phys Act. 1998;6:36-44.
9. Simonsick EM, et al. Measuring fitness in healthy older adults: the health ABC long-distance corridor walk. J Am Geriatric Soc. 2001;49:1544-1548.
10. Bittner V, et al. Prediction of mortality and morbidity with a six-minute walk test in patients with left ventricular dysfunction .JAMA. 1993;270:1702-1707.
11. Newman AB, et al. Association of long-distance corridor walk performance with mortality, cardiovascular disease, mobility limitation, and disability. JAMA. 2006;295:2018-2026.
12. Guralnik JM, et al. Lower extremity function in persons over the age of 70 years as a predictor of subsequent disability . N Engl J Med. 1995;332:556-561.
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