ABSTRACT
Adipose tissue is the largest fuel reserve in the human body. Even lean adults usually have more than 100,000 kcal of potential energy stored as triglycerides in adipose tissue, which is approximately 50-fold more than the amount stored as glycogen in skeletal muscle and liver. The use of adipose tissue as a fuel during exercise requires the coordinated regulation of triglyceride lipolysis, adipose tissue blood flow (ATBF), and skeletal muscle blood flow to enhance the delivery of released fatty acids from adipose tissue to working muscles. Adipose tissue triglycerides are an important source of fuel during exercise. The increase in lipolytic rate that occurs during exercise facilitates delivery of fatty acids from adipose tissue to skeletal muscle for oxidation. This increase in fatty acid availability to muscle requires the integration of neural, hormonal, and circulatory events. This chapter reviews the factors that regulate lipolysis of adipose tissue triglycerides, the methods used to measure whole-body and regional lipolytic activity
in vivo
, and the effect of dietary intake, obesity, aging, and endurance training on the mobilization and use of endogenous triglycerides during exercise.
