Physical Activity, Energetics and Metabolism

The Physical Activity, Energetics and Metabolism (PAEM) Research Group

High-quality nutrition and physical activity are critical in optimal growth and development in children. Correspondingly, poor nutrition and sub-optimal amounts of exercise are causative factors in the development of obesity, and improvement of these factors are vital for the reversal of obesity and its corresponding disturbances in metabolism. The aim of the Physical Activity, Energetics and Metabolism (PAEM) research group is to determine the role of physical activity in normal growth and development and in prevention of obesity in children.

The overall aim of the core is to promote life-long health, and prevent obesity and disorders through studies of:

  • energy and substrate metabolism in children and parents;
  • exercise, physical activity and nutrition effects on biochemical and physiological processes of importance for health.

The PAEM research group operates a wet lab and maintains key instrumentation and expertise for cellular and tissue bioenergetics using high-resolution respirometry; substrate fluxes using stable isotope methodology, and regular biochemical analyses.


Group Members

Elisabet Borsheim, Ph.D., Professor, Research group leader

Matthew Cotter, MS, Lab manager

Eva Diaz, M.D., MMSc, Instructor

Eugenia Carvalho, Ph.D., Instructor

Catarina Young, BS, Research Assistant


Description of Ongoing Projects

Early Life Physical Activity and Metabolic Response to Later Physical Activity

Exercise training is a cornerstone in the prevention and treatment of obesity and metabolic disturbances. The impact of early life exercise training on metabolic responses to physical activity later in life is unclear. We utilize various models to study the hypothesis that early life exercise changes the metabolic responses to later life physical activity.

Mitochondrial function in circulating cells and muscle tissue

Data from human and animal models suggests that reduced tissue mitochondrial function can be an early marker for detection of dysfunctional metabolism. It is unclear if tissue mitochondrial dysfunction can be detected using less invasive methodology. Bioenergetics profiling of readily available circulating cells has recently been proposed to reflect systemic mitochondrial health/fitness, physical function and inflammation. In this project, we study whether mitochondrial function in circulating cells is related to that measured in the muscle fibers of the same subjects, and if differences can be observed when comparing metabolic dissimilar groups.

Phenotypic and metabolic characteristics in infancy and early childhood leading to obesity

Studies have shown that children who become obese as early as age 2 years are more likely to be obese as adults. This study is supported by an R01 grant from the NIH (Co-PIs Andres and Borsheim) to determine energy intake, total energy expenditure rates, fatty acid oxidation rates, and fat mass accretion and distribution of infants and children during the first 2 years of life, while controlling for important confounding factors. Stable isotope technologies are used for measurements of the energy expenditure and fat oxidation.

Arkansas Active Kids (AAK)

Childhood and adult obesity is correlated with metabolic dysfunction, but it is not clear if this is caused by a lack of physical fitness or physical activity, rather than obesity per se. In the AAK study, the aim is to determine the independent impact of weight status, physical activity and physical fitness, respectively, on overall cardiometabolic health. In order to determine this, children on a continuum of weight status and physical activity levels, respectively, are characterized through a battery of exercise tests combined with objective measurement of physical activity and assessment of various metabolic variables.

Expecting and Glowing studies

The Expecting and Glowing studies are large cohort studies at ACNC. The PAEM lab is involved in exercise training and physical testing of mothers and children in these studies, and in the determination of energy expenditure and fatty acid oxidation rates in children using safe stable isotope technology.

Center for Childhood Obesity Prevention, Metabolism Core

Through collaborations with UAMS, ACRI and ACNC researchers, the lab is funded by NIH as the Metabolism Core of the COBRE Center for Childhood Obesity Prevention (CCOP; PI: Weber). The goal of the core is to provide support for metabolic studies, including biological sample analyses for projects in the CCOP. The Core supports and mentors CCOP junior investigators in planning and performance of metabolic studies, including use of stable isotope tracer techniques to measure metabolic rates.