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Eccentric exercise decreases maximal insulin action in humans: muscle and systemic effects
S Asp1, J R Daugaard, S Kristiansen
1Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark. sasp@aki.ku.dk
The Journal of Physiology
|August 1, 1996
Summary
Unaccustomed eccentric exercise impairs muscle and whole-body insulin action. This effect is seen at maximal insulin concentrations, suggesting a systemic factor reduces insulin responsiveness.
Area of Science:
- Exercise Physiology
- Metabolic Regulation
- Human Physiology
Background:
- Eccentric exercise, characterized by muscle lengthening under tension, can induce significant muscle damage and metabolic alterations.
- Understanding the systemic and local effects of unaccustomed exercise on insulin sensitivity is crucial for metabolic health.
- Previous studies suggest exercise impacts glucose metabolism, but the specific effects of eccentric exercise on insulin action require further investigation.
Purpose of the Study:
- To investigate the impact of one-legged eccentric exercise on both local muscle and systemic insulin action in humans.
- To determine if impaired insulin sensitivity following eccentric exercise is concentration-dependent (maximal vs. submaximal).
- To explore potential mechanisms, including local muscle adaptations and systemic factors, contributing to changes in insulin action.
Main Methods:
- Utilized the hyperinsulinemic-euglycemic clamp technique in seven healthy subjects.
- Employed arterial and bilateral femoral venous catheterization to measure muscle glucose uptake and metabolic parameters.
- Compared insulin action during a clamp following one-legged eccentric exercise (post-eccentric exercise clamp) with a control clamp without prior exercise.
Main Results:
- Maximal insulin-stimulated glucose uptake was marginally lower in the exercised thigh compared to the control thigh (P=0.08).
- Glycogen concentration was significantly reduced in the exercised thigh, and GLUT4 protein content was 39% lower in the basal state (P<0.05).
- Whole-body insulin sensitivity, indicated by the glucose infusion rate, was reduced by 15.7% following eccentric exercise (P<0.05).
Conclusions:
- Unaccustomed eccentric exercise impairs both local muscle and whole-body insulin action at maximal, but not submaximal, insulin concentrations.
- The observed systemic impairment in insulin action exceeds the local effect in the exercised muscle.
- These findings suggest the release of a systemic factor that decreases insulin responsiveness following eccentric exercise.