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Prior exercise and postprandial substrate extraction across the human leg.
D Malkova1, R D Evans, K N Frayn
1Human Muscle Metabolism Research Group, Department of Physical Education, Sports Science and Recreation Management, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom.
American Journal of Physiology. Endocrinology and Metabolism
|October 29, 2000
Summary
Prior exercise enhances the leg
Area of Science:
- Exercise Physiology
- Metabolic Studies
- Cardiovascular Health
Background:
- Postprandial hyperlipidemia is a risk factor for cardiovascular disease.
- Exercise is known to lower postprandial plasma triacylglycerol (TG) concentrations.
- The role of skeletal muscle in exercise-induced TG reduction requires further elucidation.
Purpose of the Study:
- To investigate the effect of prior exercise on postprandial substrate extraction in human skeletal muscle.
- To determine if enhanced leg TG uptake mediates the reduction in postprandial plasma TG after exercise.
Main Methods:
- Eight healthy men underwent two trials: one after a 2-hour exercise session and one control (no exercise).
- Postprandial substrate (TG, glucose) extraction across the leg was measured for 6 hours after a standardized meal.
- Femoral arterial and venous blood samples and leg blood flow were analyzed.
Main Results:
- Prior exercise significantly increased postprandial TG clearance across the leg, particularly the chylomicron fraction.
- Absolute TG uptake was maintained despite lower plasma TG concentrations post-exercise.
- Exercise also enhanced postprandial leg blood flow and glucose uptake.
Conclusions:
- Prior exercise improves postprandial TG clearance by the leg, but this effect alone does not fully explain the reduction in postprandial lipemia.
- Mechanisms beyond increased leg TG uptake are involved in exercise's beneficial effects on postprandial lipid metabolism.