Acute Effects of Postprandial Aerobic Exercise on Glucose and Lipoprotein Metabolism in Healthy Young Women

Abstract

To investigate the acute effects of postprandial exercise on glucose and lipoprotein metabolism after the intake of glucose with or without fat cream in healthy but sedentary young women. Healthy young Japanese women with a sedentary lifestyle, normal weight (18.5≤BMI<25), normal ovarian cycle, and apolipoprotein (apo) E3/3 were enrolled as participants. They ingested 1 g/kg body weight of glucose only or glucose supplemented with 1 g/kg oral fat tolerance test (OFTT) cream 4 (0.35 g/kg as fat) with or without postprandial walking exercise on a motorized treadmill (ca. 50%V(·)o(2)max for 30 min) 20 min after intake of the beverage. Each subject performed 4 trials in a randomized, cross-over design. Venous blood was drawn before (0 h), and 20 min, 1, 2, 4, and 6 h after ingestion. Postprandial exercise alleviated the sharp rise of serum glucose and insulin, and transiently mitigated the decrease of free fatty acids (FFA) after ingestion of the glucose-only beverage. Although no fat was contained in the glucose beverage, transient apoB48 secretion was observed without the rise of serum triglyceride (TG) and remnant-like particle (RLP)-TG, suggesting that apoB48-containing lipoprotein particles with little TG were released by the exercise. Serum apoB48 concentrations at 6 h had decreased to levels lower than the baseline (0 h, after 12-h overnight fast) with or without exercise, suggesting that the 12-h overnight fast may not have been a 'true' fast. Similarly, postprandial exercise suppressed the sharp rise of serum glucose and insulin, and transiently mitigated the decrease of FFA after the ingestion of glucose with OFTT cream. Postprandial exercise stimulated the transient secretion of apoB48-containing TG-rich lipoproteins (TRL) with a rapid rise of serum apoB48, TG, and RLP-TG; however, the subsequent course of lipemia was not significantly changed. Serum apoB48 and RLP-TG values did not return to the baseline even after 6 h, suggesting that postprandial lipoprotein metabolism was not finished at the end of the experiment. Postprandial aerobic exercise alleviated the glycemic peak at 1 h associated with insulin 'sparing'. The effect of exercise on fat metabolism was transient, enhancing the secretion of intestinal TRL at an early phase, but no further significant effects were observed. Postprandial exercise transiently stimulated the secretion of apoB48 after glucose intake without a fat load.