BDNF and malnutrition: Therefore, when malnutrition and exercise deficiency occur, abnormal skeletal muscle BDNF production mechanism and decreased serum BDNF levels can further lead to mitochondrial dysfunction in skeletal muscle and affect the efficacy of cardiac rehabilitation in patients with CVD (53).In summary, exercise elevates BDNF levels, which in turn play an important role in cardiovascular health and disease recovery; therefore, exercise-targeted BDNF may be a potential mechanism for its cardiac effects.