A few years ago, a weird-sounding condition called rhabdomyolysis got a lot of attention as a scary—and possibly lethal—side effect of very intense workouts, like CrossFit. If you were into this kind of thing, you may have gotten a little nervous. If not, you probably moved on with your life.
But in July, The New York Times reported on an increase in cases of rhabdomyolysis from spin class, bringing it back into the limelight. What was once a condition reserved in people’s minds for the most hardcore has now left us all wondering: “Could it happen to me?”
Rhabdomyolysis, also known as rhabdo, is essentially muscle breakdown. When you exercise, some muscle breakdown is normal, and part of the process of getting stronger, explains Nayan Arora, M.D., a nephrology fellow at the University of Washington.
When people overstress their muscles, they are at risk for the muscle tissue breaking down so much that it releases the protein myoglobin into the bloodstream. Myoglobin is toxic to the kidneys, which is why rhabdo can lead to kidney damage or complete kidney failure if left untreated, Arora explains.
While rhabdo is serious—and seriously terrifying—it’s still pretty rare, he says. That means you shouldn’t let it stop you from exercising—but you should have it on your radar. Here are four things that you need to know about rhabdomyolysis.
1. It’s not just from hardcore workouts.
Arora says there has been a slight uptick in cases of exercise-related rhabdo, likely as a result of the rise in popularity of grueling workouts, from high-intensity interval training to spinning and ultrarunning. But muscle exertion isn’t the only cause. The condition can also be a result of alcohol abuse, medications including statins and prednisone, illicit drug use, muscle diseases, trauma, certain health conditions and genetic issues, seizures and immobility, research shows.
Rhabdomyolysis was studied extensively for the first time during World War II, when researchers examined soldiers with crush injuries from the 1940 London Blitz, says Arora.
“Interestingly, rhabdo-like symptoms are mentioned in the Bible. When the Jews were crossing the desert they were eating large amounts of quail,” he says. Researchers believe the birds may have eaten hemlock, resulting in rhabdomyolysis from accidental hemlock poisoning.
Exercising in hot, humid conditions or while taking creatine supplements, ephedra diet pills, or energy drinks with high doses of caffeine also increases your risk, says Arora.
2. Dehydration puts you at a higher risk.
Usually, doing a tough workout alone won’t land you in the hospital, says Arora. Most people who get rhabdo from exercise were doing something really intense and didn’t drink enough water before and during whatever activity they were doing.
“Going all the way back to 1940 with victims of crush injuries, it was people who didn’t have access to water who had the highest risk,” says Arora.
That’s why IV fluid is the No. 1 rhabdomyolysis treatment to prevent kidney damage, he says. To protect yourself from getting rhabdo in the first place, make sure you hydrate, hydrate, hydrate.
How much water you should drink depends on a lot of factors, including your weight, fitness level and the foods you eat during the day, says Arora. But a good rule of thumb during exercise is to drink some water every time you take a break—and to give yourself those breaks even if you’re in a class that doesn’t encourage rest.
3. You won’t pee blood.
One rhabdomyolysis symptom is red or brown urine, which patients often mistake for blood, says Arora. What looks like blood is actually myoglobin, that toxin that can lead to kidney damage. When this happens, your condition has gotten serious, and it’s important to seek medical help right away, he says.
4. It can take three days to set in.
You might expect to know shortly after, or even during, a workout that something is wrong. But rhabdo usually peaks at 24 to 72 hours after a workout or injury, says Arora. Delayed-onset muscle soreness, or DOMS, is normal after a tough workout, and it can sometimes be hard to differentiate between DOMS and rhabdomyolysis, he says.
If you experience muscle pain or weakness in one muscle group that seems out of proportion to the workout, it could be rhabdo, says Arora. Swelling or a cramp-like sensation that won’t go away, especially in one muscle group, are other possible signs. If you’re sore all over, you’re probably OK, but it’s always better to err on the side of caution if you’re concerned, he says.
Rhabdomyolysis Treatment and Prevention
If you think you may have rhabdomyolysis, get yourself to an emergency room right away. Rhabdo can be fatal if left untreated, says Arora.
“Basically, the whole point of treatment is to prevent you from getting kidney damage, and the way to do it is with huge doses of fluids,” he says.
Depending on the extent of toxins released, IV fluids are usually given for two to five days. At that point, most people will have recovered. A provider will recommend patients take an exercise break. This could be a couple of weeks to a couple of months, but will depend on many factors, including the severity of the condition and a person’s fitness level. Easing back in with a provider’s guidance is always recommended, Arora says.
At the end of the day, no workout is worth dying over. Listen to your body, ease into new workouts, pay attention to hydration, take regular breaks and seek help right away if something feels wrong after a workout, says Arora.