6'3" 152 lbs, waist 28.5 inches. am fast triathlete, but recently deteriorated. was not overtraining. hungry, legs sore. ck is 500 u/l, ldh high. why muscle breakdown? low body fat? other reason?

Medication review.: Require a thorough history and physical examination by a well-trained physician with review of any medications (like statin drugs) and selection of appropriate laboratory studies.

See sports doc.: Check with you pcp if you do have rhabdomyolysis. Are you on the right diet? From the triathletes i've met, they have special diets during their training and when they compete. It might help to see a sports-oriented medical doctor.

That's thin!: That's very low body fat ( i was bike racer 6'2" 156# 31 waist , considered thin) if your ck was taken after a race it could have been elevated from the effort or a particularly hard workout. You may also be overtrained elevated ck has been suggested as a marker for overtraining but no protocol has been proven your sports medicine doctor needs to check more labs of blood and urine to start.

Listen to your body: A high ck is a sign of rhabdomyolysis, sometimes to alcohol or dehydration. See a physician who will check for nutrient deficiencies like zinc, toxic exposures, or genetic defects. Rest, eat 6 equal healthy meals with a good carb source at each meal like quinoa or spelt which are both anti-inflammatory, breathe and relax, just walk to improve circulation, and get a good night sleep.