The influence of the intensity of treadmill walking and training status on lipoprotein metabolism in the fasted and postprandial states

SIGLEAvailable from British Library Document Supply Centre- DSC:DXN003497 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Postprandial lipemia 16 and 40 hours after low-volume eccentric resistance exercise

PURPOSE: There is evidence to suggest that muscle damage caused by resistance exercise (RE) may increase postprandial lipemia (PPL). This study examined PPL for two consecutive days after a protocol of low-volume eccentric RE that caused muscle damage. METHODS: Nine healthy, untrained male volunteers aged 27.2 ± 1.1 yr performed a session of eccentric RE consisting of eight sets of inclined leg presses at six repetition maximum with 3-min rest intervals. A high-fat meal (1.2 g fat, 1.2 g carbohydrate, 0.22 g protein, and 68.6 kJ•kg -1 body mass) was administered 16 h (day 1) and 40 h (day 2) after exercise as well as after an overnight fast with no prior exercise (control condition [C]). Venous blood samples were obtained before and hourly for 6 h after each meal. RESULTS: The duration of the exercise session (including rest intervals) was 25.6 ± 0.2 min, whereas net exercise time was 4.6 ± 0.2 min. Total energy expenditure was 0.64 ± 0.04 MJ. Serum creatine kinase and ratings of perceived muscle soreness were significantly elevated on day 1 and peaked on day 2. Triacylglycerol total area under the curve was 12.1% lower on day 1 compared with C (7.51 ± 0.99 vs. 8.54 ± 1.07 mmol•L -1•6 h -1, P < 0.02), whereas no difference existed between C and day 2. Serum insulin incremental area under the curve was significantly elevated on day 2 compared with C, indicating transient insulin resistance. CONCLUSION: These results show that low-volume eccentric RE is effective in reducing postprandial triacylglycerol concentration despite the low energy expenditure. Muscle damage does not have a detrimental effect on PPL. © 2009 by the American College of Sports Medicine

Are the reductions in triacylglycerol and insulin levels after exercise related?

Moderate exercise improves insulin sensitivity and reduces triacylglycerol (triglyceride; TG) concentrations. We hypothesized that changes in insulin sensitivity are an important determinant of exercise-induced changes in postprandial TG concentrations. Altogether, 38 men and 43 women, all of whom were normotriglyceridaemic and normoglycaemic, each underwent two oral fat tolerance tests with different pre-conditions: control (no exercise) and prior exercise (90min of exercise at 60% of maximal O2 uptake the day before). Venous blood samples were obtained in the fasting state and for 6h after a high-fat mixed meal. In the control trial there were significant correlations between log fasting TG concentration and log fasting insulin concentration (r = 0.42, P < 0.0005) and between log postprandial TG response (area under the curve) and log postprandial insulin response (r = 0.48, P < 0.0005). Prior exercise reduced the fasting TG concentration by 18.2±2.2% (mean±S.E.M.) (P < 0.0005), the postprandial TG response by 21.5±1.9% (P < 0.0005), the fasting insulin concentration by 3.8±3.1% (P < 0.01) and the postprandial insulin response by 11.9±2.5% (P < 0.0005). However, there was no relationship between the exercise-induced changes in log fasting TG and log fasting insulin (r = 0.08, P = 0.50), nor between the exercise-induced changes in log postprandial TG response and log postprandial insulin response (r = 0.04, P = 0.70). These data suggest that the reductions in fasting and postprandial TG levels elicited by a session of moderate-intensity exercise are not mediated by an increase in insulin sensitivity