What to know about rhabdomyolysis in CrossFit athletes

During rhabdomyolysis, injured muscle cells release substances into the bloodstream that can affect the kidneys and body chemistry. CrossFit sessions can combine heavy resistance, high repetitions, short recovery, heat, and movements that are new to the athlete. Ordinary post-workout soreness tends to be manageable and gradually settles; rhabdomyolysis may bring disproportionate pain, marked weakness, swelling, reduced urine, or urine that looks tea-coloured or dark. Symptoms can develop after the session rather than immediately.

Stop intense exercise if these warning signs appear and seek medical advice promptly. Do not attempt to flush the problem with extreme amounts of fluid or return to training to test yourself. Tell the clinician about the workout, heat exposure, supplements or medicines, fluid intake, and when symptoms began. Until assessed, rest from strenuous exercise and follow personalised advice. Future training should build volume, intensity, and unfamiliar movements progressively, with recovery and heat management included.

Get urgent medical assessment for dark or reduced urine, severe muscle pain or swelling, unusual weakness, confusion, fainting, vomiting, or difficulty keeping fluids down after exercise. Emergency help is appropriate if you feel severely unwell, collapse, or develop breathing or chest symptoms. Blood and urine tests may be used to assess muscle injury and kidney function; symptoms alone cannot confirm the diagnosis.

Ask which tests are needed, when it is safe to resume activity, whether any medicine or supplement could increase risk, and how to modify training in heat. Ask for clear return-to-exercise signs and instructions about hydration that fit your health and treatment.