Exercise-Induced Rhabdomyolysis: A potentially life-threating condition

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“If you take on new, aggressive workouts before your body is properly conditioned, you could be at risk for developing rhabdomyolysis, a potentially life-threating medical emergency,” said Dr. Michael Richards, Major Command Aerospace Medicine Consultant.

Exertional or exercise-induced rhabdomyolysis is a medical condition frequently observed in the setting of military training and operations. This condition often occurs when the level of exertional stress is greater than the service member is accustomed to.

In 2025, a total of 521 cases of rhabdomyolysis likely associated with physical exertion or heat stress (i.e., exertional rhabdomyolysis) were identified in the U.S. Armed Forces, according to the Defense Health Agency Medical Surveillance Monthly Report.

When comparing 2025 rates to 2024, the Air Force showed the largest case increase of exertional rhabdomyolysis with incidence rates 60% higher from the previous year (2025-67 cases, 2024-38 cases).

During the DHA MSMR surveillance period, 2021-2025, approximately three-quarters (75.9%) of cases occurred during the warmer months, April – September.

What is Rhabdomyolysis?

Exertional rhabdomyolysis is a condition where skeletal muscle breaks down from prolonged or intense physical exertion and releases its contents into the bloodstream. Some of these muscle fiber components may overwhelm normal filtration of the blood, potentially resulting in severe kidney damage.

In addition, imbalances in circulating electrolytes place the individual at risk for abnormal heart rhythms and even death.

Symptoms of Rhabdomyolysis

• Severe muscle discomfort
• Weak muscles
• Muscle swelling
• Dark urine that’s brown, red or tea-colored

“Excessive muscle damage can produce swelling of muscle and surrounding tissue resulting in poor circulation. If the pressure in a muscle compartment gets too high, your tissues won’t get enough fresh blood, oxygen, and nutrients. This can lead to tissue death (necrosis), which can cause permanent damage and loss of muscle function. In some cases, surgical intervention is required to relieve the muscle compartment pressures to save the affected limbs. Go to the emergency room if you have muscle swelling and intense muscle pain,” said Richards.   

“Regarding dark urine color, it’s important to differentiate the dark urine of dehydration, which is still yellow. Conversely, the dark brown urine color after an intense workout is caused by the release of the affected muscle’s intracellular contents that is filtered through the kidneys and excreted in urine. In large quantities, these muscle components can damage your kidneys. If your kidneys can’t get rid of your body’s waste fast enough, kidney failure can occur. This can be life-threatening and requires immediate medical attention,” he continued.

Additional symptoms may include:

• Significant fatigue
• Nausea and vomiting
• Fever
• Rapid heart rate

Symptoms can range from mild to severe and usually develop one to three days after a muscle injury.

Common Causes of Exertional Rhabdomyolysis

“Rhabdomyolysis usually happens after individuals engage in physical activity that they are not used to, and they really push it too hard,” said Richards.  

He added it can also happen when people return to working out after taking some time off, and many cases are associated with both acute and chronic alcohol use.

The risk of developing exertional rhabdomyolysis is greatest for people with low body fitness who suddenly and significantly increase their physical activity levels. Workouts to create this reaction are typically excessive, repetitive or prolonged duration.

Weight-bearing exercise focusing on high-volume eccentric muscle contraction, like downhill running or lowering heavy weights, is a risk factor for rhabdomyolysis.

Strenuous physical activities in hot and humid environments can increase the risk for developing rhabdomyolysis. Heat causes faster muscle breakdown. Dehydration is also a risk factor because your kidneys can’t dispose of your body’s waste without plenty of fluids.

Use of certain medications, including statins and antidepressants, can cause muscle breakdown and lead to rhabdomyolysis.

How to avoid Rhabdomyolysis

“Rhabdomyolysis is largely avoidable with the appropriate training methods, hydration, and recovery,” said Richards.

He offers the following guidelines to reduce the risk of developing exertional rhabdomyolysis.

• Start an exercise program slowly and listen to your body. If you feel especially sore or tired during a workout, stop and rest. Don’t push yourself beyond safe limits.
• Be hydrated before beginning physical activity and stay hydrated during your workout. This will help prevent problems and help flush your kidneys.
• Talk to your healthcare provider about any medications you’re taking that may increase your risk of developing rhabdomyolysis.
• Avoid drinking alcohol. Alcohol is a diuretic, which means it will make you more dehydrated. You need more fluids in your system, not the opposite.

“Avoid fitness influencers on the internet that challenge people to take part in strenuous activities that maybe that haven’t done before. That’s where you can run into problems,” said Richards.

Caution is necessary for Peer Fitness Leaders when leading group exercise to a diverse crowd and safety must be the constant theme. Workout programs that have participants doing too much physical activity too quickly or exercise for too long, especially after little to no physical activity, can lead to negative health consequences.

For comprehensive information on exercise-induced rhabdomyolysis, visit:Exertional Rhabdomyolysis.