What should you know about lactic acid rhabdomyolysis?

During hard physical effort, muscles use energy rapidly and lactic acid is produced as part of that metabolism. The familiar burning feeling during exertion is not proof of rhabdomyolysis, and later muscle soreness is not the same process. Rhabdomyolysis occurs when muscle cells are damaged and release substances such as CK and myoglobin into the blood. The concern is the injury and its possible effect on kidney function and electrolyte balance. A clinician uses the history, examination, blood tests, and urine assessment to distinguish these situations.

Stop intense exercise if you develop unusual weakness, marked swelling, severe pain, or symptoms that feel out of proportion to the activity. Rest in a cool environment and seek medical advice when warning signs are present. Tell the clinician about the session's intensity, heat, hydration, new training, medicines, supplements, and any injury. Do not use ordinary post-workout soreness as a reason to dismiss worsening symptoms, and do not resume hard training until you have been advised that it is appropriate.

Seek urgent care for dark or reduced urine, severe muscle pain, rapidly increasing swelling, pronounced weakness, vomiting, confusion, fainting, chest pain, or breathing difficulty. These findings can accompany significant muscle breakdown or another urgent problem. A symptom's presence does not identify its cause, so assessment should focus on the warning sign and the person's overall condition.

Could my symptoms reflect muscle injury rather than normal exertion? Do I need CK, kidney-function, electrolyte, or urine testing? When can I restart exercise? Which changes should send me to urgent care?