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Exercise-induced modulation of antioxidant defense.
1Department of Kinesiology, Interdisciplinary Nutritional Science, and Institute on Aging, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA. ji@soemadison.wisc.edu
Annals of the New York Academy of Sciences
|April 27, 2002
Summary
Oxidative stress contributes to sarcopenia, or age-related muscle loss. Exercise and antioxidant supplements can help aging muscles maintain function by boosting antioxidant defenses.
Area of Science:
- Gerontology
- Skeletal Muscle Physiology
- Oxidative Stress Biology
Background:
- Skeletal muscle aging leads to sarcopenia, impacting mobility and quality of life.
- Oxidative stress, driven by reactive oxygen species (ROS) and reduced antioxidant defenses, is a key factor in sarcopenia.
- Aging muscle exhibits diminished cell signaling, impairing antioxidant enzyme gene expression despite increased ROS.
Purpose of the Study:
- To investigate the role of oxidative stress in age-related muscle decline (sarcopenia).
- To explore how exercise and antioxidant supplementation influence antioxidant defenses in aging muscle.
Main Methods:
- Review of research on oxidative stress, aging muscle, and exercise.
- Analysis of redox-sensitive signaling pathways and antioxidant enzyme expression (e.g., Mn-SOD) post-exercise.
- Examination of training adaptations in aging muscle antioxidant systems.
Main Results:
- Nonexhaustive exercise induces mild oxidative stress, activating signaling pathways that enhance antioxidant enzyme expression.
- Exercise, particularly repeated bouts, increases de novo protein synthesis of antioxidant enzymes.
- Aging attenuates but does not eliminate training adaptations in antioxidant enzymes.
Conclusions:
- Oxidative stress is a significant contributor to sarcopenia.
- Exercise is beneficial for enhancing antioxidant defenses in aging muscle via redox-sensitive pathways.
- Supplementation with exogenous antioxidants may be necessary to optimize defense in senescent muscle.