In July, The New York Times set off a firestorm with a story about spin classes. This wasn’t a trend piece on the hottest workouts or a how-to for cycling newbies; the impassioned reactions from readers were in response to the reported facts on a condition called rhabdomyolysis.
Otherwise known as rhabdo (or “Uncle Rhabdo,” as it’s commonly referred to in the Crossfit community), rhabdomyolysis is a serious medical issue that’s on the rise, thanks in part to extreme endurance workouts like indoor cycling.
What is Rhabdo?
“Rhabdomyolysis is the condition that results from the breakdown of muscle tissue due to excess exercise, crushing trauma, or medications,” says Stephanie Long, MD, a family medicine doctor at One Medical in San Francisco. “Initial symptoms can be very subtle, but include muscle weakness, fatigue, soreness, bruising, and changes to your urine, with low urine output or infrequent urination, and dark, tea-colored urine.”
Those initial indicators are just the beginning though. When rhabdo turns severe, it can result in life-threatening kidney damage. If those subtle signs progress to fever, nausea, vomiting, confusion, agitation, or just an overall feeling of unease (otherwise known as malaise), rhabdo might be to blame.
Can Exercise Really Cause Rhabdo?
The controversy in the comments section of the Times piece was mainly rooted in a seemingly contradictory concept: exercise-caused illness. But it’s true; while drugs like cocaine and traumatic injuries can lead to rhabdo, the National Institutes of Health lists “severe exertion, such as marathon running or calisthenics” as a potential cause, too. And the publicized concern over cycling-induced rhabdo is rooted in research: a recent paper published in The American Journal of Medicine described three unusual cases of rhabdo, all occurring after a new cycler’s first spin class.
But before blame was directed at popular studio spin classes, people were buzzing about the infamous association that resulted in Uncle Rhabdo serving as Crossfit’s unofficial mascot. “I’ve treated cases of rhabdo after Crossfit and spinning,” says Long. “In both cases, patients were new to the activity and participating in their first class. They didn’t have the calibration to the activity or their own intensity levels. Afterwards, they had worsening pain out of proportion to being sore, tense muscles, and dark, tea-colored urine.”
It’s hard to deny an association, but can anyone go so far as to say causation is involved? “I would never go so far as to say that Crossfit causes rhabdo, or that their programs are designed in such a way that there is an innate risk of rhabdo, or that anyone who does Crossfit is highly likely to get rhabdo,” says Tarquin Thornton-Close, owner and head trainer at Triptych Strength. “A more appropriate statement would be, ‘anyone who is brand new to very intense exercise and is de-conditioned, or people pushing very far past their limits, is more at risk for rhabdo.’”
How Common is Rhabdo?
According to the largest data set on the condition, a retrospective review of U.S. Army soldiers between 2003 and 2006, just 0.2% developed rhabdo, which scales up to about 7 or 8 cases out of 10,000 every year (and just 2 cases out of 10,000 when translated to the civilian population). But another study reported 29 emergency room visits for exercise-induced rhabdo at NewYork-Presbyterian alone between 2010 and 2014 (14 of which resulted from indoor cycling).
So with the ever-increasing popularity of super-intense workouts, is rhabdo really on the rise?
“We have been seeing rhabdo in more recreational athletes in recent years due to the prevalence of more higher intensity workouts,” says Long. “While training at this level is effective for weight loss and conditioning, any new activity needs to be started at a more moderate level and increased as tolerated.”
How to Reduce Your Rhabdo Risk
They key to avoiding rhabdo and minimizing your risk for all sorts of injuries, big and small, is, as Long says, to “start low and go slow.” Going from zero to Tour de France doesn’t happen overnight, so be patient and persistent and progress will occur over time.
“Always start off at a level that you can handle, and gradually progress from there,” says Thornton-Close. “The body is amazing at adapting to a given stimulus, but it still needs time to do that. It’s almost like driving a stick shift car; you can’t go from first to fifth gear right away. You have to progress through second, third, and fourth to get there; same thing with the human body.”
This article is not intended to substitute for informed medical advice. You should not use this information to diagnose or treat a health problem or condition. Always check with your doctor before changing your diet, altering your sleep habits, taking supplements, or starting a new fitness routine.