ROS Signaling and Exercise Adaptation: The Physiological Basis of HIIT and MICT Responses

Abstract

Reactive oxygen species (ROS) are reactive molecules that play an important role in the physiological response to physical exercise. Although ROS are commonly associated with oxidative stress and cellular damage, recent scientific evidence suggests that ROS also function as signaling molecules that mediate metabolic, mitochondrial, and cardiometabolic adaptations during exercise. This literature review aimed to analyze the role of ROS signaling in exercise adaptation, particularly in high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), from the perspective of exercise physiology and redox biology. The review employed a narrative literature review approach through article searches in Scopus, PubMed, ScienceDirect, and Google Scholar databases published between 2018 and 2026. A total of 24 eligible articles were qualitatively analyzed based on their focus on redox signaling, mitochondrial adaptation, molecular pathways, and cardiometabolic responses to exercise. The findings demonstrated that physiological levels of ROS activate signaling pathways including AMPK, PGC-1α, Nrf2, MAPK, and NF-κB, which contribute to mitochondrial biogenesis, endogenous antioxidant enhancement, insulin sensitivity, and metabolic efficiency. HIIT generally induces a greater and more rapid oxidative stimulus that promotes stronger molecular adaptation, whereas MICT produces a more stable and sustained redox response. Both exercise modalities provide beneficial effects on cardiometabolic health through distinct adaptive mechanisms. Therefore, ROS signaling represents an essential physiological component linking exercise stimuli to metabolic and mitochondrial adaptation.