Does walking decrease the risk of cardiovascular disease hospitalizations and death in older adults?

OBJECTIVES: The purpose of this study was to determine whether walking is associated with a reduced risk of cardiovascular disease hospitalization and death in community-dwelling older men and women.
DESIGN: A prospective study, with follow-up time of 4 to 5 years (average 4.2 years).
SETTING: A western Washington health maintenance organization. PARTICIPANTS: Men and women aged 65 years and older from a random sample of HMO enrollees invited by mail to participate in a health promotion intervention trial (36% accepted the invitation and completed questionnaires). This report is based on 1645 older adults without severe disability and without history of heart disease. Vital status ascertainment was complete (100%), and only 2.6% did not complete the follow-up. MEASUREMENTS: Reported frequency and duration of walking for exercise, work, errands, pleasure, and hiking in the 2 weeks before baseline were used to classify hours of walking per week. The two main outcomes were: (1) cardiovascular disease hospitalizations with a discharge diagnosis of coronary (ICD-9-CM 410-414) or other cardiovascular diseases (ICD-9-CM 390-409, 415-448) documented by computerized hospitalization records and (2) death. Numerous potential confounding factors were considered, including age, sex, treated high blood pressure, current estrogen use and chronic disease score (ascertained by computerized medical and pharmacy records), and ethnicity, education, income, physical function, self-rated health status, smoking, alcohol intake, and body mass index (ascertained by self-report on the mailed questionnaire).
RESULTS: Walking more than 4 hours/week was associated significantly with a reduced risk of cardiovascular disease hospitalization in both sexes combined compared with walking less than 1 hour/week (age and sex-adjusted relative risk = 0.69; 95% confidence interval, 0.52-0.90). This association was not altered by adjustment for baseline cardiovascular risk factors and indicators of general health status. The association was present in all age groups, among those with and without physical limitations, and also among those who did and did not also participate in more vigorous physical activities. Walking more than 4 hours/week was also associated with a reduced risk of death (age and sex-adjusted relative risk = 0.73; 95% confidence interval, 0.48-1.10), however, this association was substantially diminished by adjustment for cardiovascular risk factors and measures of general health status.
CONCLUSIONS: Walking more than 4 hours/week may reduce the risk of hospitalization for cardiovascular disease events. The association of walking more than 4 hours/week with reduced risk of death may be mediated by effects of walking on other risk factors. These findings provide much stronger evidence than previously available for advising older men and women to embark on or maintain a sustained program of walking to prevent cardiovascular disease events.