That was nearly the case for US Paralympian Amy Purdy. While training hard during snowboarding season late last year, Amy noticed some muscle soreness and swelling after pushing herself hard during a series of pull-ups.
“I almost didn't come to the hospital when I did because my symptoms were so mild,” she wrote in a post on Instagram. “Had I of decided to sleep it off l most likely would have had major kidney failure or even gone into shock by the next morning.”
She was suffering from rhabdomyolysis, colloquially referred to as rhabdo, which is when muscle tissue breaks down and enters the bloodstream, damaging the kidneys.
“The scary part about rhabdo is there isn't anything the Dr's can do to stop it once it begins and they don't know how bad it will get. They can only support your body with constant IV fluids to try to buffer the effects, but your muscles continue to swell and break down and your kidneys are still forced to filter the massive amount of toxins.”
Luckily, her kidneys held up like a champ, she said.
“This condition is so scary, please pay attention to your body,” she added. “If you have overworked your muscles, if you are sore and you can see some swelling even the slightest amount like I had, don't hesitate to go to the ER, it can save your life.”
Additional symptoms of rhabdomyolysis include dark, reddish urine, a decreased amount of urine and general weakness.
Dr Rob Eley from The University of Queensland says that over a decade ago, cases of rhabdo were few and far between, mostly associated with marathon runners and army training camps. However, he says there has been a marked increased thanks to the growing popularity of high-intensity resistance training like CrossFit.
While rhabdo can be fatal, he says that without pre-existing disease it normally "follows a benign course" with treatment including intravenous fluids and rest. However it can be exacerbated by amphetamines, alcohol, extreme temperatures, dehydration and infections.