Myocardial sarcoplasmic reticulum Ca2+ATPase function is increased by aerobic interval training

OBJECTIVE: Reduced activity of the sarcoplasmic reticulum Ca ATPase-2a (SERCA-2a) contributes to myocardial dysfunction. Exercise training improves myocardial Ca-handling, but SERCA-2a function is uncertain. We assessed SERCA-2a activity after exercise training. METHODS: SERCA-2a function was assessed by sarcoplasmic reticulum Ca uptake in cardiomyocytes with other Ca uptake mechanisms blocked, in mice after aerobic interval training versus sedentary controls. RESULTS: We established protocols to assess SERCA-2a function, and show that aerobic interval training increases the maximal rate of Ca uptake by 30%. This is at least partly explained by reduced phospholamban-to-SERCA-2a ratio. CONCLUSION: Aerobic interval training improves myocardial SERCA-2a performance, explaining at least partly why myocardial Ca-handling improves after exercise training.