Cross‐Sectional Associations of Objectively Measured Sedentary Time, Physical Activity, and Fitness With Cardiac Structure and Function: Findings From the Dallas Heart Study

Abstract

Background Physical inactivity and low cardiorespiratory fitness (CRF) are associated with higher risk of heart failure. However, the independent contributions of objectively measured sedentary time, physical activity, and CRF toward left ventricular (LV) structure and function are not well established. Methods and Results We included 1368 participants from the DHS (Dallas Heart Study) (age, 49 years; 40% men) free of cardiovascular disease who had physical activity and sedentary time measured by accelerometer, CRF estimated from submaximal treadmill test, and cardiac magnetic resonance imaging performed using 3‐T magnetic resonance imaging. A series of linear regression models were constructed to evaluate the associations of sedentary time, moderate physical activity, vigorous physical activity, and CRF with LV parameters after adjustment for established cardiovascular risk factors. We observed a modest correlation between CRF levels and objectively measured moderate (correlation coefficient, 0.17; P <0.001) and vigorous physical activity (correlation coefficient, 0.25; P <0.001) levels. In contrast, sedentary time was not associated with CRF. In adjusted analysis, both vigorous physical activity and higher CRF were significantly associated with greater stroke volume, LV mass, LV end‐diastolic volume, and lower arterial elastance, independent of other confounders. Sedentary time and moderate physical activity levels were not associated with LV parameters. Conclusions Vigorous physical activity and CRF are significantly associated with cardiac structure and function parameters. Future studies are needed to determine if interventions aimed at improving CRF levels may favorably modify cardiac structure and function.

Associations between physical activity, sedentary behaviour and left ventricular structure and function from the Echocardiographic Study of Latinos (ECHO-SOL)

“…This evidence taken together with our study confirms that staying active is more strongly associated with favourable measures of cardiac structure and function even at the level of light PA. Our improved LV strain, LV remodelling, LA volume, and improved diastolic function align with Dallas heart study results. 7 These results further support the physiological benefits of long-term aerobic exercise and PA on cardiac structure and function. Importantly prior study also showed that only MVPA but not sedentary time were significantly associated with CRF levels.…”

“…Increases in LA size associated with higher CV fitness and MVPA have been described. [4][5][6][7] In the general population, however, increased LA size is associated with many pathological conditions, and it is usually the result of two processes, either increased volume or increased cardiac filling pressures. Interestingly, similar to our findings, the Cooper Clinic Longitudinal study observed no apparent association between diastolic dysfunction and LA size among high-fit individuals.…”

“…Interestingly, similar to our findings, the Cooper Clinic Longitudinal study observed no apparent association between diastolic dysfunction and LA size among high-fit individuals. 4 Our findings and those reported by others suggest that LA dilation mechanisms may reflect physiology unrelated to diastolic function (ie, greater cardiac output) with higher PA. [4][5][6][7] Recently Dallas Heart Study, which included 1368 participants (age, 49 years; 40% men, free of CVD), showed that objective measures of MVPA (assessed by accelerometer) were positively associated with more favourable LV structure and function parameters (assessed cardiac MRI), with better LV contractility, higher SV, lower arterial elastance, and LVH without myocardial injury, independent of traditional CVD risk factors. 7 Vigorous PA was also positively associated with higher SV and lower effective arterial elastance measures and greater likelihood of both LVH without myocardial injury and malignant LVH.…”

“…3 PA is associated with cardiovascular (CV) health benefits, including prevention of age-related cardiac remodelling, systolic and diastolic dysfunction, adaptive pro-hypertrophic effect, decreased markers of inflammation, improved metabolic health, decreased risk of heart failure (HF) and improved overall survival. [4][5][6][7][8] Physical inactivity is associated with obesity, diabetes, hypertension and the metabolic syndrome. [9][10][11] All these conditions share several underlying mechanisms that result in increased HF risk; insulin resistance, impaired energy availability, endothelial dysfunction, oxidative stress, which ultimately leads to increased myocardial stiffness, left ventricular (LV) hypertrophy (LVH), diastolic dysfunction and an increased propensity for coronary artery disease.…”

Patterns of Accelerometer-Measured Physical Activity and Health Outcomes in Adults: A Systematic Review

“…The most common comparison ( n = 7) (25,26,32,34,44,45,60) was between physical activity intensity categories labeled as “light” and “moderate-to-vigorous.” These categories were based on counts per minute thresholds, which the individual threshold value varied across studies. Four studies compared two or more intensities and adjusted for intensity (25,29,54,60). However, total volume of physical activity was not adjusted for in any analytical model.…”