The CPK blood test is a muscle enzyme (chemical) that is found specifically inside muscle cells. Everyone has a certain level of CPK in their blood because of the normal turnover of muscle cells. People with more muscles have a higher level of CPK in the blood. Anything that damages muscle cells can increase the CPK in the blood. Trauma, heavy workouts (seen in soldiers who march for long periods), intramuscular injections, alcohol, viral infections, autoimmune diseases called myositis. Some drugs such as cholesterol drugs (statins) can cause muscle damage as a rare side effect. There are also people with genetic problems who have an increase tendency to raise thier CPK after exercise, but this rarely is a problem. In short answer to your question, it depends on how high the CPK level, and if it is signficantly high, then there needs ot be an evaluation of why. I would speak with your doctor
About Alan Matsumoto, M.D.
Part-time Faculty, Division of Rheumatology
Johns Hopkins University