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Physical Activity and Heart Disease Risk Among Older Adults | Journal Scan
Study Questions:
Do regular physical activity and sedentary behaviors influence risk for coronary heart disease (CHD) among older adults?
Methods:
Data from the LIFE (Lifestyle Interventions and Independence for Elders) study of 1,635 participants from eight US locations, were used for the present analysis. Participants were ages 70-89 years at enrollment and at high risk for mobility disability measured through low-extremity functional limitations. Physical activity and sedentary behavior were measured via a triaxial accelerometry worn at the hip for a minimum of 7 consecutive days. Sedentary behavior was defined as accelerometry counts of <100 counts/minute. Physical activity was divided into two intensity groups (100-499 counts/minute and ≥500 counts/minute). The primary outcome of interest was predicted 10-year CHD risk, as defined by the Framingham Risk Score.
Results:
A total of 1,170 participants, mean age 79 years (66.1% women), were included. Participants averaged 109 ± 9.0 accelerometry counts/minute, and were sedentary most of the day (77% of the time the accelerometer was worn). Time spent engaged in physical activity was an average of 138 ± 43 minutes/day for accelerometer counts/minute between 100-499 and 54 ± 37 for physical activity of ≥500 counts/minute. No participants engaged in moderate to vigorous activity defined by the National Health and Nutrition Examination Survey as >2020 counts/minute. Each minute per day of sedentary behavior was associated with an increased risk of 10-year CHD risk among adults with a prior history of cardiovascular disease (CVD) (0.04%, 95% confidence interval [CI], 0.02%-0.05%), and among those adults with no prior history of CVD (0.03%, 95% CI, 0.02%-0.03%). Physical activity duration (both 100-499 counts/min and ≥500 counts/min) was associated with lower CHD risk for both adults with and without CVD. However, the mean number of counts/minute of physical activity was not significantly associated with CHD risk. The investigators did note an interaction between sex and count frequency among those without CVD, such that intensity of activity was associated with risk for women, but not for men.
Conclusions:
The authors concluded that sedentary time was associated with 10-year risk for CVD among older adults with mobility limitations. In terms of physical activity, duration rather than intensity was associated with a lower risk for CVD in this population.
Perspective:
As expected, older adults who are at risk for functional disability are highly sedentary. Tailoring interventions to improve duration of physical activity may reduce risk for CHD. Further research to determine if outcomes such as myocardial infarction and stroke are reduced with regular physical activity is warranted.
Keywords: Coronary Artery Disease, Coronary Disease, Accelerometry, Motor Activity, Mobility Limitation, Sedentary Behavior, Risk, Aging, Geriatrics, Physical Fitness
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