Skeletal muscles use redox signaling to communicate and coordinate how to respond when you exercise. During aerobic exercise, muscles consume more oxygen so they can up their ATP production to sustain continued muscle contractions. As oxygen metabolism increases, muscle cells naturally generate small amounts of RONS (reactive oxygen and nitrogen). But a small, temporary increase of RONS does not cause oxidative damage. In fact, just the opposite. Because redox signaling tightly controls when, where, how much, and for how long RONS act, they function as important signaling messengers to regulate energy production, muscle repair, and exercise adaptation, rather than causing damage.
How Redox Signaling Drives Endurance Adaptation Biology
At excessive levels, RONS can cause cellular damage. However, during exercise, redox signaling tightly controls RONS production in order to direct cellular responses and maintain healthy muscle function. For example, when you exercise, a temporary increase in RONS signals muscle cells to produce more energy. This, in turn, activates genes that produce more mitochondria, leading to quicker and faster ATP production–this is one of the reasons why endurance improves with regular exercise.
RONS molecules activate very specific cellular pathways such as AMPK, which is an energy sensor, and MAPK, which switches on genes involved in cellular growth, repair, and adaptation. With repeated exercise, these cellular pathways are strengthened as they repeatedly respond to the demands of exercise. Over time, a process called mitochondrial biogenesis can occur, which increases the number of mitochondria your body creates and directly affects how much ATP you can efficiently produce. AMPK and MAPK pathways strengthen muscular communication between nerves and muscle and also encourage the formation of new blood vessels in order to deliver more oxygen and nutrients to working muscles. It is these coordinated efforts–redox signaling, RONS molecules, and the AMPK and MAPK pathways–that impact muscle strength and endurance.
Factors That Influence Redox Signaling and Muscle Adaptation
Both the intensity and duration of physical exercise will influence redox signaling. Essentially, the more intense and long the workout is, the stronger the signaling, adaptation response, and ROS production will be. An isolated workout creates a temporary increase in reactive oxygen and nitrogen species (RONS) that activate signaling pathways that trigger energy production, muscle repair, and recovery. However, with regular exercise, these repeated signals lead to long-term adaptations that improve mitochondrial function and increase muscle strength and endurance. You’ll want to stay in the “optimal zone” for signaling and ROS production, where repeated, moderate exercise leads to adaptations that strengthen redox signaling pathways and not oxidative stress. Large ROS spikes and strong signaling put you at higher risk for oxidative stress.
Research also suggests that taking high doses of antioxidant supplements around the same time you exercise may reduce some of the necessary signaling needed for long-term adaptation. Antioxidants, like vitamin C and E, can neutralize ROS. f you block ROS too much, especially with high doses of antioxidants during or right after exercise, you may limit these adaptations.
The ultimate goal is not to eliminate RONS, but to use them wisely to maintain healthy homeostasis and support cellular communication without causing oxidative stress.
Redox regulation has a major role in muscle adaptation during exercise
Redox regulation is crucial for how our bodies use oxygen to produce energy, especially in muscles, where this process is essential. Studies highlight that reactive oxygen and nitrogen species (RONS) play a key role in signaling muscle adaptation during exercise. Understanding these signals has been a major focus of scientific research. This review aims to explain how RONS activate specific pathways in muscles that lead to adaptation, such as creating more energy-producing mitochondria, remodeling muscles, forming new blood vessels, regenerating nerves, and the impact of external antioxidants on these processes.
