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In recent years, 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 a consistent member of an intense-training gym, it might have rightfully caused some nervousness.
But recently, there have been reports of rhabdomyolysis in people participating in less hardcore activities like spin classes. Or maybe you saw the athlete in that episode of “The Pitt” rushed to the hospital with symptoms of rhabdomyolysis. All of this might have you wondering: “Could rhabdo happen to me?”
What is rhabdomyolysis?
Rhabdomyolysis, also known as rhabdo, is essentially muscle breakdown. When you exercise, some muscle breakdown is normal and part of getting stronger.
But when people overstress their muscles, they risk 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.
Here’s some interesting history: Rhabdomyolysis was first described by doctors treating people with severe crush injuries during World Wars I and II. They found that many patients who survived the crush injury often died several days later of kidney failure. Looking closely at their kidneys, it was found that their renal tubules were choked with myoglobin.
This finding led them to treat victims of crush injuries with fluids to prevent myoglobin and other toxins from accumulating in the kidneys, which remains the standard treatment today.
And while rhabdo is serious — and seriously terrifying — it’s still pretty rare. That means you shouldn’t let it stop you from exercising, but having it on your radar is good.
Here are four things to know about rhabdomyolysis:
1. It’s not just from hardcore workouts.
There has been a slight uptick in cases of exercise-related rhabdo, likely because 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.
Rhabdo can be caused by anything that results in muscle damage, including trauma and crush injuries, dehydration and heat stroke, viral infections (including COVID-19) and some inherited conditions. Use of prescription drugs, such as statins, or illicit drugs, such as methamphetamine and cocaine, can also cause rhabdo.
2. Dehydration puts you at a higher risk.
A challenging workout alone usually won’t land you in the hospital. Most people who get rhabdo from exercise are doing something really intense and don’t drink enough water before and during their training.
“When your body is dehydrated, there is less blood perfusing the kidneys as well as the muscles,” says Nisha Bansal, MD, a nephrologist at Kidney Care & Transplantation Services at UW Medical Center – Montlake.
Dehydration can also weaken your kidneys’ ability to clear out myoglobin, leading to toxic effects. 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.
3. You’ll have darkened urine
Bansal says that changes in your urine may be an indicator of rhabdomyolysis.
“This can include a reduced frequency and amount of urine production, and dark, tea-colored urine,” she says.
Patients often mistake this red or brownish-colored pee for blood, but it’s 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.
4. It can take three days to set in.
You might think you would 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. Delayed-onset muscle soreness, or DOMS, is normal after a tough workout, and it can sometimes be hard to differentiate between DOMS and rhabdomyolysis.
If you experience muscle pain or weakness in one muscle group that seems out of proportion to the workout, it could be rhabdo.
“In addition to muscle pain or muscle weakness, and changes to urine, some other symptoms include fatigue, nausea and confusion,” says Bansal.
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.
How to prevent and treat rhabdomyolysis
If you think you may have rhabdomyolysis, get yourself to an emergency room right away. Rhabdo can be fatal if left untreated.
“In the short term, people can develop acute kidney injury, which is a temporary reduction in kidney function,” says Bansal. “Acute kidney injury can lead to fluid imbalances and changes in electrolyte levels.”
Depending on the severity of the injury, IV fluids are usually given for two to five days. At that point, most people will have recovered. Your doctor will recommend an exercise break. This could be a couple of weeks to a couple of months, but depends 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.
“Most people make a full recovery with appropriate care,” says Bansal. “However, if the damage is severe or a person has an underlying chronic kidney disease, this could pose a higher risk for long-term kidney disease.”
That’s not to scare you, but it is a reminder to listen to your body during times of intense heat or physical stress and do what you can to prevent it from happening in the first place.
IV fluid is the number one rhabdomyolysis treatment to prevent kidney damage. 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. 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.
The Takeaway
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 immediately if something feels wrong after a workout.
This article was originally published on Oct. 11, 2017 by Kristen Domonell and updated on Sept. 15, 2023. It has been reviewed and updated with new info. Ari Cofer contributed to this article.
