For starters, it does not have teeth and claws. But are you at risk? Sure thing.

By Lauren Mazzo
August 22, 2017
Photo: Shutterstock

It's the digital era, which means that staying on top of health news usually includes learning about something new that's going to kill you every single day. (Yay!) One of the latest viral stories, however, has people pointing fingers at something that we've come to know as the ultimate way to get healthier: exercise.

In July, the New York Times reported on a recent study in the American Journal of Medicine about the uptick in cases of rhabdomyolysis (the dreaded "rhabdo" that you've probably heard about) happening as a result of spin class. The story went viral. People everywhere suddenly became deathly afraid of SoulCycle.

But rhabdo shouldn't scare you away from the spin bike forever. It's an uncommon condition, though we currently don't have a great idea of the prevalence in the American public. The most recent stats-a 2012 study on army recruits undergoing basic training-show the incidence rate at about 0.2 percent. However, while it's rare, rhabdo is a serious condition that every active person (or person who wants to be active) should understand.

What Is Rhabdomyolysis?

At its core, rhabdo simply means the breakdown of muscle tissue, says Alexis Colvin, M.D., an orthopedic surgeon specializing in sports medicine at Icahn School of Medicine at Mount Sinai and the chief medical officer for the U.S. Tennis Association. As muscles break down, they release the enzyme creatine kinase (CK) and a protein called myoglobin into your bloodstream, which can lead to three serious health complications:

  1. Kidney failure: ICYDK, your kidneys filter your blood and produce urine. Myoglobin floating around in your blood stream can filter into your kidneys, damaging them, says Denise Pate, M.D., a physician at the Medical Offices of Manhattan and a certified spin instructor. This could ultimately lead to kidney failure-the biggest risk associated with rhabdo.
  2. Acute compartment syndrome: Think of your limbs as separate compartments that can be further divided into smaller compartments (your thigh, your lower leg, ankle, etc.). If enough swelling occurs in one section, it can halt anything going in and out (effectively creating a compartment shut off from the rest of your body). This can cause nerves, veins, and arteries in the area to die, says Dr. Pate, which may result in permanent and extensive muscle damage in the area.
  3. Electrolyte abnormalities: When your muscles break down, they can also release potassium and phosphorous into your blood, says Dr. Pate. Potassium control is super important for your heart to function correctly. Too much potassium in your blood could eventually lead to a heart arrhythmia (a heart rhythm problem which can become dangerous if it affects the heart's ability to function, causing dizziness, fatigue, chest pain, shortness of breath, or even cardiac arrest).

What Causes Rhabdomyolysis

The type of rhabdo we're talking about here-exertional rhabdo-is when muscle breakdown is caused by strenuous exercise, says Dr. Colvin. Other causes of rhabdo could be from trauma, drugs, genetic muscle diseases, or seizures, according to the National Institutes of Health. Occasionally, nutritional supplements (namely weight-loss aids like Hydroxycut) have caused rhabdo, too. (These new e-stim "workouts" are under fire for causing rhabdo as well.)

The main risk you have to worry about, though, is going too hard, too fast with a new type of exercise. Dehydration can also play a part in increasing your risk. "I think it has a lot to do with how conditioned the person is," says Dr. Pate. "Frequently, in rhabdo cases, you're seeing people who are exercising hardcore for the first time, initially starting exercise, or starting a new type of exercise." (See these warning signs that you're pushing yourself too hard in the gym.)

It's worth noting that even experienced athletes are at risk: Paralympic snowboarder Amy Purdy was diagnosed with rhabdo in October 2016. "Usually, it's from eccentric exercise-where you're contracting and lengthening the muscle at the same time, like in plyometrics," says Dr. Colvin. "You usually don't hear about marathon runners getting rhabdo." (Perfect example: One woman got rhabdo from a grueling pull-up workout.)

That's why exercise built around intense bursts-such as spinning and CrossFit-have been under fire for rhabdo in these recent examples.

Rhabdomyolysis: Symptoms and Treatment

There are three key symptoms to look out for (and all require immediate medical attention).

  1. Muscle pain: Yeah, that post–leg day ache can be a b*tch. But if you're experiencing much more pain than usual, along with swelling or joint pain, it might be time to take this more seriously than your usual DOMS (delayed-onset muscle soreness).
  2. Muscle weakness: Ditto with muscle weakness. There's a difference between having kinda-lazy arms after a day of boxing and barely being able to move your limbs. Keep track of what's normal for your body so you know what's out of the ordinary.
  3. Dark-colored urine: While dark yellow urine can sometimes be an indicator that you're dehydrated (See: 6 Things Your Pee Is Trying to Tell You) in this case, it means something more serious. When myoglobin (a dark-colored molecule) overwhelms your kidneys, it gets released into your urine, changing the color, says Dr. Pate. If your urine is tea-, cola-, or red-colored, or if you're peeing much less than usual, see your doctor, stat.

Other symptoms can include swelling, fever, and nausea, says Dr. Colvin. If left untreated, rhabdo may go away on its own-in fact, many people are unaware that they have it and don't seek care. However, there's a much greater risk of developing complications if you don't get treated. The only way to be 100-percent sure whether you have rhabdo or not is to get checked out at an ER (and keep in mind that it's better safe than sorry). A doctor can diagnose you with a physical exam and by testing your blood and urine levels of creatine, CK, myoglobin, and potassium.

"If you suspect symptoms of rhabdo I would never recommend waiting it out to see if it will clear up on its own," says Pate. "Since hydration is the main form of treatment, you cannot compare the difference between hydrating by drinking versus IV fluids in a hospital setting."

If you wind up in the ER with rhabdo, you can expect to undergo intense rehydration. If ingesting fluids via mouth isn't enough, you'll get an IV. In severe cases, you'll need dialysis (a machine that will filter your blood and do the kidney's job for you), says Dr. Pate.

And though it might not need saying, you can't go straight back to the gym. Every case is different, but you could end up staying in the hospital for anywhere from 24 hours to a few days. Once you're released, doctors will likely recommend that you take at least one to two weeks off from exercise, says Dr. Pate.

How to Prevent Rhabdo

"Listen to your body," says Dr. Pate. A group fitness atmosphere or one-on-one trainer may have you pushing past your comfort zone-in a bad way. If you haven't exercised in a while or you're starting something new, ease your way into it, says Dr. Pate. (Watch for nine signs that you're overtraining.)

When you do head to a workout, hydrate before, after, and during the class, recommends Dr. Pate. (Remember: If you're feeling thirsty, that means you're already dehydrated.) Also: Because hot and humid environments may increase your risk, don't go from zero to hot yoga. Steer clear of drugs and alcohol before a tough workout (should be a given) and be wary of supplements.

And remember: Exercise is supposed to make your body feel better. Torturous, tough workouts are fun and satisfying in their own way-but in the end, you should exercise for your health, not your ego.