Hello dear Understand your concern CPK is creatine phospho kinase enzyme (energy metabolism enzyme) mainly present in the skeletal muscle, smooth muscle, myocardium, photoreceptor cell of retina, inner ear etc. Normal CPK range is 22-170 Iu/L. So you have raise CPK. In you case I think it is due to muscle strain due to swimming (increase muscle strain in upper arm and lower arm muscle) and stress as you have not chest pain (so no myocardial infraction). Take following advice by consulting the MD physician Rest for few days and drink lots of fluid (10-12 glass per day), give rest to clf and upper arm muscle, drink cocconut water, do exercise that strengthen your muscle, tablet vitamin E plus carnitine. After above advice repeat the CPK test after one month. If still it will come high then you should rule out the other causes like: Hypothyroidism, excess steroid/ cushings syndrome, myopathies, motor neuron disease, idiopathic, Macro CK in healthy individual, idiopathic case without any disease. So take above advice and consult the the doctor for proper follow up to rule out other causes. Hope this may help you Best regards Dr. Sagar