The prevalence of obesity continues to rise in the United States. Total and abdominal obesity increase the risk for coronary heart disease and mortality among women. Moreover, there is an accumulation of fat in the abdominal region during the aging process with an increase in the infiltration of fat around and within skeletal muscle which adversely affects glucose and lipoprotein metabolism. A main focus of my research is the study of obesity, body fat distribution, intramuscular fat and their role in insulin resistance with emphasis on the effects of weight loss and exercise training on muscle and glucose metabolism in sedentary, overweight individuals. The basic research includes the study of mechanisms by which diet and exercise interventions (aerobic and resistive training) affect skeletal muscle and adipose tissue metabolism, insulin signaling and gene expression in muscle, and in vivo insulin action in sedentary older individuals.
In addition, my research involves the study of residual hemiparesis following stroke which leads to physical deconditioning and possibly muscle atrophy and abnormal metabolism due to disuse or aberrant neural innervation. We have described skeletal muscle atrophy and greater fat deposition within the muscle of the hemiparetic limb in chronic hemiparetic stroke patients which may contribute to functional disability and increased cardiovascular disease risk in chronic hemiparetic stroke patients. We are currently examining the muscle molecular phenotype and its relationship to gait deficit severity and interventions designed to prevent muscle atrophy and reduce insulin resistance which are needed to minimize the loss of functional independence and cardiovascular disease risk in older chronically disabled stroke patients.