Abstract

Intensive physical exercise induces structural remodeling of the myocardium accompanied by oxidative stress and inflammatory responses, which may impair cardiac adaptation and recovery. This study evaluated the protective effects of Spirulina supplementation on exercise-induced myocardial alterations using morphological and biochemical assessments in an experimental model. Histological examination demonstrated that prolonged intensive exercise caused myocardial fiber disorganization, interstitial inflammatory infiltration, and increased collagen deposition, accompanied by morphometric changes in cardiomyocytes. Digital morphometric analysis revealed a reduction in the proportion of cardiomyocytes (from 38.7% in controls to 28.7% following intensive exercise) and an increase in fibroblast distribution (from 32.3% to 40.3%), indicating early myocardial remodeling. Spirulina supplementation partially restored myocardial architecture, reduced structural damage, improved morphometric parameters, and attenuated biochemical indicators of oxidative stress and tissue injury. These findings suggest that Spirulina exerts cardioprotective effects against exercise-induced myocardial remodeling, most likely through antioxidant, anti-inflammatory, and cytoprotective mechanisms, supporting its potential use as a metabolic support strategy for individuals exposed to intensive physical activity.