Exercise-induced oxidative stress in humans: cause and consequences.

Area of Science:

• Exercise Physiology
• Cellular Biology
• Biochemistry

Background:

• Oxidative stress and damage to macromolecules in blood and skeletal muscle are known consequences of prolonged or high-intensity exercise.
• The precise sources of reactive oxygen species (ROS) production during exercise are still debated, though contracting skeletal muscle fibers are implicated.

Purpose of the Study:

• To explore the role of oxidative stress in skeletal muscle during exercise.
• To investigate the sources and functions of reactive oxygen species (ROS) in muscle contraction and adaptation.

Main Methods:

• Review of existing literature on exercise, oxidative stress, and ROS production in skeletal muscle.
• Analysis of evidence implicating various cellular components (mitochondria, NADPH oxidase, etc.) in contraction-induced ROS generation.

Main Results:

• Compelling evidence suggests that muscular activity promotes oxidant production in contracting skeletal muscle fibers.
• While specific sites of ROS production remain debated, mitochondria, NADPH oxidase, PLA₂-dependent processes, and xanthine oxidase are potential contributors.
• Contraction-induced ROS generation is physiologically important for regulating muscle force and exercise-induced adaptations.

Conclusions:

• Exercise-induced oxidative stress is a well-established phenomenon with significant implications for skeletal muscle.
• Reactive oxygen species (ROS) act as crucial signaling molecules in skeletal muscle, influencing both immediate function and long-term adaptations to training.
• Despite 30 years of research, the complete role of ROS in skeletal muscle physiology continues to be an active and expanding area of study.