| Obesity is linked to lower lipid oxidation and elevations in resting and postprandial triglyceride (TG) concentrations, and is associated with many chronic disease risks including CVD. Exercise is commonly used to overcome such disruptions in lipid dynamics, but the comparison of various exercise modalities and their role in rectifying such metabolic inadequacies is scarce. Using the ingestion of isotope labeled [U-13C] palmitate, we investigated postprandial TG and fatty acid (FA) metabolism and the contributing hormonal changes from an acute bout of endurance (E) and resistance (R) exercise in obese women. In comparison to a sedentary control condition, we found significantly elevated exogenous and endogenous derived lipid oxidation during the postprandial period in both E and R. Analysis of plasma FA and TG concentration revealed significant attenuations in endogenously derived TG, and elevations in exogenously derived plasma FA. The only significant change as a function of condition in hormone concentration during the postprandial period was for growth hormone (GH), which was significantly elevated in both E and R in comparison to a sedentary control. While combining both E and R within the same exercise session in a chronic exercise regimen results in improvements in body composition and fitness, there is still considerable debate as to whether there is a benefit to performing E either before or after R. We investigated the concurrent ordering (E-R, R-E) of 60 min combined E + R during an 8-week intervention to determine potential differences in body composition and physical fitness in inactive women. We found that combined E and R significantly increased aerobic capacity, upper and lower body strength, as well as FFM regardless of the order they were performed. In summary, compared to a sedentary control, a pre-meal bout of exercise enhances the postprandial rise in growth hormone in obese women. This is associated with enhanced whole body fatty acid oxidation and reduced appearance of only endogenously derived TG in the bloodstream. These results were unaffected by type of exercise (E or R). In a separate study of combined E and R, the order of exercise had no impact on fitness parameters and both groups improved over an 8-week intervention. Collectively, these data suggest that E and R have equivalent and beneficial effects on postprandial fat trafficking and physical fitness in untrained women. |
