Synergistic Effects of Omega-3 Fatty Acids and Physical Activity on Oxidative Stress Markers and Antioxidant Mechanisms in Aged Rats

Background: Aging induces degenerative processes in the body, contributing to the onset of various age-associated diseases that affect the population. Inadequate dietary habits and low physical activity are major contributors to increased morbidity during aging. This study aimed to investigate the combined effects of omega-3 fatty acid supplementation and physical activity on the markers of oxidative stress and antioxidant defense mechanisms in aged male Wistar rats (23–24 months). Methods: The rats were randomly divided into four experimental groups: a sedentary control (placebo, no exercise), a trained (placebo and moderate-intensity graded aerobic exercise; Ex), and two trained groups supplemented with low (160 mg/kg of body weight; O1 + Ex) and high (320 mg/kg of body weight; O2 + Ex) doses of omega-3 fatty acids. The biochemical and functional parameters related to sarcopenia and the markers of oxidative stress were measured in blood and gastrocnemius muscle. Results: The results demonstrated dose-dependent, synergistic effects of omega-3 fatty acid supplementation and physical activity. The higher dose (320 mg/kg of body weight) improved plasma antioxidant capacity (TEAC, +21.01%, p < 0.01) and GPx activity (+78.05%, p < 0.05) while reducing CAT activity in erythrocytes (−19.92%, p < 0.05), likely as an adaptive stress response. Combined interventions also normalized cholesterol levels, improved the functional parameters of sarcopenia (stride length, +14.82%, p < 0.001), and enhanced antioxidant protection in aged rats. Conclusions: These findings highlight the potential of combining omega-3 fatty acid supplementation and physical activity to counteract aging-related degenerative changes. Further research is needed to elucidate the underlying mechanisms and evaluate the long-term benefits of these strategies in aging populations.