On avarege, how long will serum CK values remain elevated in Exertional Rhabdomyolysis, & is the CK always elevated with it?

Hello Tanya, you've posed a very deep question. I am assuming you have some knowledge of exertion rhabdomyolysis. As such I believe you will find the following articles/abstracts of interest to you.

I hope they prove helpful responding to your question.

Serum Creatine Kinase Levels and Renal Function Measures in Exertional Muscle Damage
CLARKSON, PRISCILLA M.1; KEARNS, AMY K.1; ROUZIER, PIERRE2; RUBIN, RICHARD2; THOMPSON, PAUL D.3

ACSM Position Statement on Exertional Heat Illness During Training and Competition

http://journals.lww.com/acsm-msse/Fulltext/2007/03000/Exertional_Heat_Il...