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BETHESDA, MD — Physicians and healthcare leaders across the Military Health System have developed a new clinical practice guideline for the management of exertional rhabdomyolysis (ER), a dangerous condition that occurs when the muscles work too hard and begin to break down.
The updated Clinical Practice Guideline (CPG) for the Management of Exertional Rhabdomyolysis in Warfighters, released in September 2025, was developed by the Uniformed Services University, in collaboration with the U.S. Army Heat Center and other DoD partners through the Warrior Heat- and Exertion-Related Events Collaborative based at Uniformed Services University’s Consortium for Health and Military Performance (CHAMP), according to a press release from the university.1
This new, comprehensive, standardized, evidence-based playbook can help doctors and healthcare staff recognize, treat and manage ER in military servicemembers. The guidelines also can be applied to high-performance athletes.
A diagnosis of ER is made when there are severe muscle symptoms (pain, stiffness and/or weakness) and laboratory evidence of myonecrosis with a creatine kinase (CK) level greater than or equal to 5,000 IU/L in the setting of an immediate, significant exercise history. ER occurs when demanding activity, such as intense training, heavy labor or combat conditions, causes muscle fibers to break down and release their contents into the bloodstream. If ER is left untreated, it can quickly result in kidney damage, chemical imbalances in the body or life-threatening complications, the medical experts explained.
“We are very pleased to release this 2025 Rhabdomyolysis CPG update, which presents multiple significant changes and additions from our 2020 product,” Francis O’Connor, MD, MPH, professor of military and emergency medicine and medical director at Uniformed Services University’s CHAMP, said in the press release. “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.”
The new CPG offers several resources to medical teams, such as clear diagnostic standards to help doctors recognize ER earlier and more accurately in addition to risk categories that sort patients into low or high risk based on lab results and clinical signs. It also provides tools such as the McMahon Score, which combines test results and patient information to predict the chance of kidney injury, as well as step-by-step flow charts and decision aids that simplify this complex clinical situation, the press release pointed out.
The medical experts noted that although the guideline was created with military servicemembers in mind, the information has broad applications to civilians, including athletes, firefighters, first responders or other individuals engaged in high-intensity physical activity.
The updated guideline is designed for use by primary care, emergency medicine, sports medicine and operational clinicians across the military. Command medical leaders can also refer to the CPG to help shape policies around training, selection and deployment cycles. In addition, the guidelines can be used by civilian physicians, athletic trainers and occupational health providers who are seeking guidance.
In 2024, the Medical Surveillance Monthly Reports (MSMR) found the incidence rates of ER per 100,000 person-years among U.S. active-component servicemembers fluctuated from 2019 to 2023. The rates reached a low of 38.0 cases in 2020 and peaked at 40.5 cases in 2023. Starting in 2020, incidence rates per 100,000 person-years gradually increased, by 1.8% in 2021 (38.7 cases), 5.3% in 2022 (40.0 cases) and 6.6% in 2023 (40.5 cases). In 2023, subgroup rates were highest among men less than 20 years old, non-Hispanic black servicemembers, Marine Corps or Army members, and those in combat-specific and other occupations, with incidence rates 6 to 10 times greater than all other servicemembers, according to the CPG.
The CPG identifies high-risk patients who require close monitoring in the hospital as those with extremely elevated muscle enzymes, signs of compartment syndrome, kidney damage or complicating factors like sickle cell trait (SCT). High-risk criteria for hospital admission consideration include CK greater than or equal to 20,000 IU/L, suspicion for potential compartment syndrome, McMahon Score greater than or equal to 6, laboratory evidence of acute kidney injury (AKI), dark urine or confirmed myoglobinuria, metabolic abnormality (e.g., hyperkalemia, hyperphosphatemia, acidosis), SCT carrier and unreliable patient follow-up (e.g., warfighter lives alone, unit in field-exercise training), the guideline reported.
Other patients, especially those at lower risk, can be safely managed without hospitalization through limited physical activity, oral fluid intake and follow-up care within 24 to 72 hours, the experts recommended.
The medical team suggested that serum CK is the “gold standard” for diagnosis and monitoring of ER, and serum myoglobin is best used for risk prediction. The CPG update also endorses a CK greater than or equal to 5,000 IU/L in conjunction with an appropriate clinical history to diagnose ER in a warfighter. Clinicians should also note that normal baseline and post-exercise CK levels vary by age, sex, race and/or type of exercise.
The framework for return-to-duty decisions is one of the most important components of the guideline, the experts explained. The CPG recommends for low-risk patients to progress gradually from rest to reconditioning, while higher-risk patients should 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 heat stroke, prior to the development of this CPG, return-to-duty guidance was lacking,” Army Lt. Col. David DeGroot, MD, director of the Army Heat Center, said in the press release. “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 CPG pointed out that it’s important for clinicians to recognize the difference between ER and rhabdomyolysis as an end organ injury from exertional heat illness (EHI). Properly identifying ER or EHI is clinically significant, but also affects military profiling and return-to-duty decisions. Because these distinctions can be challenging, it’s critical to consult with clinicians experienced with heat-related illnesses and ER.
While most servicemembers who experience ER will recover and safely return to duty, the medical experts emphasized that some servicemembers could experience significant AKI and/or muscular injury. AKI could put servicemembers at risk for future chronic kidney disease (CKD), and some muscular injuries may result in persistent functional deficits. Servicemembers may also be at risk for future recurrence, which may limit their effectiveness and possibly predispose them to future serious injury, including permanent disability or death. Recurrence could also compromise a military unit’s mission, according to the CPG.
- O’Connor, F.G., Raleigh M., & Oh R. (2025) Clinical Practice Guideline for the Management of Exertional Rhabdomyolysis in Warfighters. Consortium for Health and Military Performance (CHAMP), Bethesda, MD. https://www.hprc-online.org/resources-partners/whec/clinical-care/clinical-practice.