Interactions between reactive oxygen species generated by contractile activity and aging in skeletal muscle?

SIGNIFICANCE: Aging leads to a loss of skeletal muscle mass and function that causes instability, increased risk of falls, and need for residential care. This is due to a reduction in the muscle mass and strength that is primarily due caused by a decrease in the number of muscle fibers, particularly, type II fibers, and atrophy and weakening of those remaining. RECENT ADVANCES: Although increased oxidative damage was originally thought to be the key to the aging process, data now indicate that reactive oxygen species (ROS) may be one of the several components of the degenerative processes in aging. The skeletal muscle shows important rapid adaptations to the ROS generated by contractions that are attenuated in aged organisms and transgenic studies have indicated that overcoming these attenuated responses can prevent the age-related loss of muscle mass and function. CRITICAL ISSUES: Elucidation of the mechanisms by which the skeletal muscle adapts to the ROS generated to contractions and the way in which these processes are attenuated by aging is critical to the development of logical approaches to prevent age-related loss of muscle mass and function. FUTURE DIRECTIONS: Future studies are likely to focus on the redox regulation of adaptive pathways and their maintenance during aging as an approach to maintain and improve muscle function.