Hi, i am a marathon runner 44 years old, 1.73 h, 58 kgr and i have cpk 3000, i dont feel tired, my rest pulses are 40-43 as usual. Last two weeks i have lost 2kgr , my diet is good, i sleep well. Last year , day after my marathon race (2.56 pb), cpk was 2800. I will run at Athens marathon Greece at two weeks, i want to know if must worried about cpk levels. Last month cpk was 650 after 30 km long run. I dont use medicine, drugs, steroids, only electrolytes. My training schedule has duration 17 weeks.