Starting moderate-intensity workouts a few times a week didn't prevent cardiovascular events for sedentary, functionally-limited older adults, a trial showed.
The rate of events -- including fatal and nonfatal myocardial infarction, angina, stroke, transient ischemic attack, and peripheral artery disease -- was no better over a mean 2.6 years with a moderate-intensity physical activity intervention than with a healthy-aging education intervention (14.8% versus 13.8%, hazard ratio 1.10, 95% CI 0.85-1.42).
The same was true for a composite of the hard endpoints of myocardial infarction, stroke, and cardiovascular death (4.6% with exercise versus 4.5% with education, HR 1.05, 95% CI 0.67-1.66), Anne Newman, MD, MPH, of the University of Pittsburgh Graduate School of Public Health, and colleagues reported in JAMA Cardiology.
But the flop of their LIFE trial for cardiovascular outcomes shouldn't discourage physicians or patients from efforts to establish a walking and weight training regimen, the researchers argued. Along with prior studies showing numerous benefits of exercise on the heart, primary results from LIFE showed an 18% reduction in incidence of major mobility disability and possibly a cognitive advantage as well.
"It is possible that exercise needs to be started earlier in life to reduce heart attacks and strokes, or that even more exercise is needed," said Newman in an email to MedPage Today. She went on to clarify that, despite these findings, "studies of cardiac rehab do show that recurrent heart attacks are prevented with exercise."
The intervention appeared to work better too for participants who were frailer, as determined by a low Short Physical Performance Battery (SPPB) score (P=0.006 for interaction).
For those who scored less than 8 on the SPPB scale, the broad cardiovascular event endpoint occurred in 14.2% of participants with the physical activity intervention and in 17.7% with the education intervention (HR 0.76, 95% CI 0.52-1.10). For those who scored better (8 or 9 on the SPPB), cardiovascular events occurred in 15.3% of participants with the physical activity intervention and in 10.5% of participants with the education intervention (HR 1.59, 95% CI 1.09-2.30).
It is possible that the greater benefit gained from physical activity among patients who were frailer at baseline was caused by a higher level of exertion applied by members of this subgroup to their prescribed exercise regimens, the researchers suggested.
The Lifestyle Interventions and Independence for Elders (LIFE) study included 1,635 sedentary participants recruited from eight different field centers, who were between the ages of 70 and 89 years and at high risk for mobility disability but still able to walk unaided. The majority of the participants were female (67%).
Participants were randomly assigned to either a physical activity intervention, comprised of twice-weekly visits to a center for walking as well as balance, strength, and flexibility training and three or four additional workouts at home, or health education classes weekly for the first 6 months then monthly thereafter.
Individuals' cardiovascular health was measured at baseline, and then again every 6 months.
"The major benefit of a walking program for people over 70 is in reducing disability and improving mobility," Newman commented.
As previously reported in the trial's primary outcome, the physical activity intervention proved to ward off mobility disability more effectively than the education intervention did. While only 30.1% of the physical activity group experienced major mobility disability, 35.5% of the education group experienced major mobility disability (HR 0.82, 95% CI 0.69-0.98).
It is possible that for physical activity to impact CV health, interventions have to be implemented earlier in life, and with more intensity than the one administered to participants of the LIFE study, the researchers suggested.
Several limitations of the study were addressed in the article. One was the short average follow-up period of 2.6 years for each participant, and another was the limited scope of the statistical power used to determine differences between various subgroups.
Supoprt for the research was provided by the University of Pittsburgh, New York University School of Medicine, Louisiana State University, University of Florida in Gainesville, Tufts University, Wake Forest School of Medicine, Stanford University, and Northwestern University.
The researchers disclosed no relevant relationships with industry.
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