Obesity is a primary etiology of many adverse health outcomes. The body has two primary types of fat tissue: subcutaneous fat and visceral fat. Subcutaneous fat is the adipose tissue that lies below the surface of the skin, whereas visceral fat is the adipose tissue that lines the internal organs. Visceral fat, compared to subcutaneous fat, is more deleterious as it is associated with cardiometabolic disorders, such as diabetes and cardiovascular disease.
Among the various types of visceral fat, pericardial adipose tissue (PAT), or the adipose tissue surrounding the heart and the coronary arteries, has recently been identified as having important health implications. PAT more actively releases inflammatory cytokines and free fatty acids than other visceral fats. Given the anatomical proximity to the heart and coronary arteries, PAT is associated with adverse cardiovascular outcomes, such as coronary atherosclerosis and coronary artery calcification. Also, PAT is associated with cardiovascular disease and diabetes, independent of obesity status. Therefore, it is important to identify lifestyle strategies to prevent excessive PAT accumulation for disease prevention and management.
It is well documented that high levels of moderate-to-vigorous intensity physical activity and low levels of sedentary behavior are related to more optimal (i.e., healthier) fat distribution and lower risk of cardiovascular and metabolic diseases. However, little is known about the impact of moderate-to-vigorous intensity physical activity and sedentary behavior on PAT. Further, no studies have examined if light-intensity physical activity is related to PAT. This is an important gap in knowledge, as emerging evidence has highlighted the favorable effects of light-intensity physical activity on some cardiometabolic health outcomes.
Our study, published in the June 2022 issue of Medicine & Science in Sports & Exercise®, examined cross-sectional and longitudinal associations of sedentary behavior and physical activities, both light and moderate-to-vigorous intensity, with PAT. We examined 6,057 multi-racial adults from the Multi-Ethnic Study of Atherosclerosis (MESA). Weekly volumes of sedentary behavior and physical activity were measured using the MESA Typical Week Physical Activity questionnaire, and PAT was estimated using computed tomography (CT) scans.
In cross-sectional analyses, we found that high sedentary behavior and low moderate-to-vigorous intensity physical activity were associated with high PAT, irrespective of sociodemographic information, key health conditions, abdominal fat and other sedentary/activity domains. We did not find any longitudinal associations between sedentary behavior/physical activity and PAT. However, among white participants only, light-intensity physical activity was longitudinally associated with low PAT.
Our findings suggest that maintaining the healthy lifestyle behaviors of reducing sedentary time and increasing physical activity of any intensity may be beneficial for preventing excessive accumulation of PAT and subsequent cardiovascular disease. The association between light-intensity physical activity and PAT in whites may be explained by the known difference in fat distribution across races or larger sample size for whites in our study. Additional research using accelerometers to objectively measure light-intensity physical activity and its relation with PAT is needed as it is difficult for people to accurately recall light-intensity activities.
Minsuk Oh, PhD, is a postdoctoral research associate in the Department of Public Health at Baylor University in Waco, Texas. He received his Ph.D. in health and human physiology at the University of Iowa under the supervision of Dr. Kara M. Whitaker. Dr. Oh’s research examines physical activity and physical functioning trajectories during the midlife and older adult years, associations of physical functioning or physical activity with health outcomes and how physical activity throughout the life course can facilitate healthy aging trajectories. He has been a member of ACSM since 2017.
Kara M. Whitaker, PhD, MPH, is an assistant professor in Health and Human Physiology at the University of Iowa. She received her Ph.D. and MPH in exercise science from the Arnold School of Public Health at the University of South Carolina. She completed a postdoctoral fellowship in cardiovascular disease epidemiology at the University of Minnesota. Dr. Whitaker’s research aims to better understand the determinants and health effects of modifiable behaviors (e.g., sedentary behavior, physical activity, sleep) to inform behavioral interventions to improve health outcomes in at risk-populations. She has been a member of ACSM since 2011 and fellow since 2021.
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