The Effects of Accumulated and Continuous Bouts of Aerobic Exercise and Differing Levels of Exercise Intensity on Postprandial Lipemia

Abstract

The purposes of this investigation were to compare the effects of low- and moderate-intensity exercise and accumulated versus continuous aerobic exercise on postprandial lipemia in males with metabolic syndrome. Fourteen middle-aged males with characteristics of metabolic syndrome (BMI = 34.3 ± 5.6 kg/m2; % fat = 37 ± 4; waist circumference = 110.2 ± 10.9 cm; TG = 217 ± 84 mg/dL; HOMA = 6.3 ± 3.8) first completed a non-exercise control condition in which they reported to the laboratory in the postabsorptive state for a fasting blood sample, consumed a high-fat test meal and then had postprandial blood samples taken at two-hour intervals for the next six hours. Participants also completed the following exercise conditions in a randomized order by treadmill walking: 1) a continuous moderate-intensity session, 2) a continuous low-intensity session, 3) two accumulated moderate-intensity sessions. Approximately 500 kcals were expended during all exercise conditions. Participants reported back to the laboratory approximately 13 hours following the completion of exercise for each condition for test meal consumption and serial blood sampling as described for the control condition. A minimum of one week and a maximum of two weeks separated subsequent conditions for each participant. Fasting and postprandial concentrations of triglycerides, insulin and glucose were analyzed using ANOVAs with repeated measures on both condition and time. Additionally, total and incremental area under the curve scores were calculated for both triglycerides and insulin and analyzed using one-ways ANOVAs with repeated measures on condition. The a priori significance level for all analyses was set at p < 0.05. The incremental triglyceride area under the curve was reduced by 27% following low-intensity exercise. Triglyceride concentrations were also reduced by 22% and 21% at the four-hour postprandial timepoint following low- and moderate-intensity exercise, respectively. No significant differences in triglyceride parameters were observed following two sessions of moderate-intensity exercise. Also, no significant alterations in insulin or glucose concentrations as a result of any of the exercise conditions were observed in this study. These results indicate that 500 kcals of aerobic exercise is sufficient to alter postprandial lipemia in men with metabolic syndrome. This outcome can be achieved through low- or moderate-intensity exercise performed in a single session. However, accumulating moderate-intensity exercise does not appear to effectively attenuate postprandial lipemia in this population.