What Is Rhabdomyolysis—and Why Do CrossFitters Keep Getting Diagnosed With It?

Every few months and years, news pops up of athletes in the emergency room getting treated for rhabdo. In the past week alone, rhabdo has been in the news twice. On September 23, USA Today reported that 12 members of the Tufts University lacrosse team were diagnosed with the condition after an on-campus training. On September 25, People Magazine broke the news that a person's arm “exploded” after an intense CrossFit workout (called the Murph Challenge)—she was later diagnosed with the same thing. Earlier this year, even a contestant on The Bachelor, Medina Alam, shared her experience with rhabdo.

Rhabdo often affects those doing super intense workouts that involve heavy physical exertion. And, to be clear, this type of exercise can be beneficial for certain people who have experience working out with that level of intensity—and if you're someone who loves it, keep doing what you're doing! But it's important to pay attention to how your body feels during your workout and be careful not to push yourself too hard.

One concerning trend: research shows that CrossFit seems to be repeatedly linked¹ to rhabdo cases. The CrossFit subreddit is rife with accounts of rhabdo. While a CrossFit publication notes that the percentage of CrossFitters who get rhabdo is tiny, one study² says “the number of cases of rhabdomyolysis after CrossFit exercise are increasing as CrossFit has been adopted by many gyms and training centers.”

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Why does this community-oriented and challenge-focused modality appear to have such a potential dark side? To understand why, it’s worth knowing a little bit more about rhabdo.

What is rhabdomyolysis?

The specific condition that crops up linked to exercise is actually called exertional rhabdomyolysis (ER), “which is basically a breakdown of skeletal muscle due to strenuous exercise or normal exercise under extreme circumstances,” says Scott Cheatham, PhD, DPT, NASM-CPT, a professor of kinesiology at California State University, Dominguez Hills.

If muscles are extremely overworked, the muscle fibers can break down. They then enter your bloodstream, but your kidneys—which are responsible for filtering the blood and flushing out byproducts in your urine—can’t actually process that protein byproduct. So this can lead to kidney failure.

What are the symptoms of rhabdo?

Physicians look for three primary symptoms: “muscle pain and/or swelling, dark brown urine, and muscle weakness,” Cheatham says. Swelling with rhabdo can be extreme; Alam’s arm contained 12 pounds of swelling. “Other possible symptoms may include, but are not limited, to fever, malaise, confusion, nausea, and vomiting.”

What to do if you think you have rhabdomyolysis

Don't be stoic or brush off your concerns—it's time to seek out care immediately. "ER is considered a medical emergency, and individuals should seek our medical care ASAP," Cheatham says.

Who's at risk for getting rhabdo?

No matter the exercise modality, going too hard, too fast is what puts people at risk for rhabdo. That means putting the pedal to the metal when you’re trying a new form of exercise, rather than ramping up slowly. That can also be the case for experienced exercisers who jump back into something full throttle after taking a break.

“Researchers have documented that strenuous or extreme exercise by inexperienced or deconditioned individuals may be a risk factor along with training in extreme outdoor environments such as hot and humid weather,” Cheatham says. “For example, an inexperienced individual may try a new type of vigorous exercise, such as high-intensity interval training, and overexert themselves, which could be a risk factor.”

Is there a connection between rhabdo and CrossFit?

Any type of exercise can cause rhabdo if a person overexerts themself at such an extreme level. Unfortunately, there are a few things about CrossFit that raise some red flags. Cheatham specifically notes that “overtraining with heavy weightlifting, resistance exercise, and endurance training, may also be risk factors for ER.”

Combining all three of those modalities is actually a hallmark of CrossFit, especially in CrossFit challenges, such as the Murph workout, where you complete a one-mile run, 100 pull-ups, 200 push-ups, 300 air squats, and another one-mile run as fast as you can. (This is the challenge that most recently sent a woman to the hospital.)

One study² also notes that eccentric muscle contraction (the lowering phase of an exercise) can be a rhabdo risk factor. CrossFit has plenty of moves that emphasize these types of moves, such as pull-ups, lowering heavy objects, GHD sit-ups, and more.

CrossFit and rhabdo: The bottom line

Researchers are concerned about the prevalence of rhabdo in CrossFit, but anyone can get this condition regardless of modality if they're inexperienced or out of practice and attempting a massive fitness challenge.