Introduction:
Despite the importance of physical activity (PA) for cardiovascular health, there is a scarcity of data on objectively measured PA in women with myocardial infarction (MI). We aim to describe 24-hour PA patterns and examine their variation by demographic and psychological factors in women with MI.
Methods:
Participants were enrolled in an ongoing multicenter trial of stress management in women with a history of MI. Participants completed self-reported psychological measures and 7-days of wrist-actigraphy monitoring (GT3X, Actigraph) at baseline (≥2 months post-MI). PA volumes were defined as the average vector magnitude (VM) counts per minute (cpm), a metric incorporating movement across all three axes of the accelerometer. This approach minimizes loss of information related to use of cut-points and describes accumulated 24-hour PA volumes. Hourly VM cpm were plotted to visualize 24-hour PA patterns and compared by age groups, race, elevated depressive symptoms (Patient Health Questionnaire-9 ≥5), and high stress levels (top quartile of Perceived Stress Scale-10). Due to the skewness, VM cpm were log-transformed and linear regression analysis was conducted to identify correlates of overall 24-hour PA.
Results:
Analyses included 85 participants (age = 59.9 ± 13.0, 20% African American, 16% participating in cardiac rehabilitation, 70% elevated depressive symptoms, 25% high stress). Patterns of PA across 24 hours differed by age, race, stress and depressive symptoms (Figure 1). For example, African American women with MI had peak PA later in the day than non-African American women, and less PA overall. Women with high (vs. low) stress had less PA overall and a less pronounced evening drop in PA, which may affect sleep. Those with elevated (vs. low) depressive symptoms showed lower PA levels, especially during the late afternoon and evening. After adjusting for age, race and cardiac rehabilitation, overall 24-hour PA volumes (log of average VM cpm) were significantly lower with higher stress (b = -0.26, p = 0.02) and elevated depressive symptoms (b = -0.22, p = 0.04).
Conclusion:
These findings may be considered to identify women with MI who may benefit from interventions to increase PA, which could reduce risk of recurrent CVD. Our data on timing of PA may be helpful in the tailored design of such programs.
Physical activity, sedentary behavior and risk of coronary artery disease, myocardial infarction and ischemic stroke: a two-sample Mendelian randomization study