When muscles work too hard, they can actually begin to break down — a dangerous condition known as exertional rhabdomyolysis, or ER. Left untreated, ER can quickly lead to kidney damage, chemical imbalances in the body or even life-threatening complications.
Now, doctors and medical leaders across the Military Health System have a newly released, comprehensive, standardized, evidence-based playbook to help them recognize and manage ER in service members. The Clinical Practice Guideline for the Management of Exertional Rhabdomyolysis was developed by the Uniformed Services University, in collaboration with the Army Heat Center and other Department of War partners through the Warrior Heat- and Exertion-Related Events Collaborative based at USU's Consortium for Health and Military Performance.
"We are very pleased to release this 2025 Rhabdomyolysis CPG update, which presents multiple significant changes and additions from our 2020 product," said Dr. Francis O'Connor, professor of military and emergency medicine and CHAMP medical director. "Our joint service team of DOW providers, representing hundreds of years of military relevant experience, has worked very hard to share the most current evidence-based information to our military colleagues to optimize the diagnosis and initial management of warfighters impacted by exertional rhabdomyolysis, and importantly, facilitate return to duty decisions."
ER occurs when strenuous activity, such as intense training, heavy labor or combat conditions, causes muscle fibers to break down and release their contents into the bloodstream. Early warning signs may include extreme muscle pain, weakness or very dark urine. In severe cases, ER can lead to acute kidney injury, requiring hospitalization or even dialysis.
Although the guideline was created with warfighters in mind, it also has broad applications in the civilian world. Athletes, firefighters, first responders and anyone engaged in high-intensity physical activity may face similar risks, making the resource valuable beyond the military.
The new Clinical Practice Guideline gives medical teams:
- Clear diagnostic standards to help doctors recognize ER earlier and more accurately.
- Risk categories that sort patients into low or high risk based on lab results and clinical signs.
- Tools like the McMahon Score, which combines test results and patient information to predict the chance of kidney injury.
- Step-by-step flow charts and decision aids that simplify what can be a complex clinical situation.
Patients at high risk — those with extremely elevated muscle enzymes, signs of compartment syndrome, kidney damage or complicating factors like sickle cell trait — require close monitoring in the hospital. Others, especially those at lower risk, may be safely managed outside the hospital through rest, hydration and follow-up care within 24 to 72 hours.
One of the most important parts of the guideline is its framework for return-to-duty decisions. Low-risk patients progress gradually from rest to reconditioning, while higher-risk patients follow a tailored plan developed with input from specialists.
"At the Army Heat Center, we frequently see cases of exertional rhabdomyolysis, either secondary to heat illness or on its own. Unlike exertional heatstroke, prior to the development of this CPG, return-to-duty guidance was lacking," said Army Lt. Col. [Dr.] David DeGroot, Army Heat Center director. "Now, providers have a resource to help as they work to return the injured warfighter to duty as quickly as possible, but without jeopardizing their health or increasing risk of reoccurrence."
The guideline is designed for use by primary care, emergency medicine, sports medicine and operational clinicians across the military. Command medical leaders can also use it to help shape policies around training, selection and deployment cycles. Civilian physicians, athletic trainers and occupational health providers may also find it a valuable reference.