Gym junkie’s arms ‘explode’ while doing pull-ups for Crossfit challenge: ‘This was a wake-up call’

She got swole — and not in a good way.

A South Carolina woman had to be hospitalized after her arms “exploded” while she was doing pull-ups for a high-intensity Crossfit routine.

“I didn’t know what was going on,” Jessica Johnson, 25, told Kennedy News Agency of the distressing incident, which occurred last month. “I was definitely shocked and didn’t know that this could happen.”

The Charleston-based Crossfitter had reportedly been participating in the Murph Challenge, a cross-training regimen that involves running a mile, completing a circuit of 300 squats, 200 push-ups and 100 pull-ups, and then running another mile afterward.

This full-body quadrathlon went seriously awry for Johnson during the pull-up phase. “I was doing 10 sets of five pull-ups,” recalled the healthcare worker, who said she “left the gym pretty tired” as she hadn’t worked out her arms like that “in a while.”

Indeed, the next day, Johnson’s arms were super sore and swollen — something she had never experienced before.

Despite getting preternaturally pumped up, the gym bunny initially didn’t think anything of it. “I thought ‘I haven’t done pull-ups in forever, it was a hard workout, they’ll go down, it’s fine,” the Southerner said.

But when she went to take a shower and brush her teeth, Johnson noticed that she couldn’t straighten her arms all the way.

Meanwhile, her swelling snowballed over the next few days to where people compared her to the Hulk.

“Everyone said ‘we just thought you were super jacked or something,’” recounted the distraught exercise enthusiast, who noticed that her pee had turned a “weird” hue as well.

“It was darker, almost like an orangery color,” said Johnson. “I was drinking tons of water but I wasn’t peeing much during the day.”

It wasn’t until the workout buff lost feeling in her hands that she finally reported to the hospital. Doctors reportedly took one look at Johnson’s arms and said she needed to go to the ER immediately.

Subsequent blood tests and other exams revealed that Johnson’s extreme body “blow-up” was due to rhabdomyolysis, a life-threatening condition where muscles break down and release toxic chemicals into the bloodstream.

Often caused by high-intensity exercise — which medics were certain was the case with Johnson — rhabdo can result in organ failure and even death.

“In rhabdomyolysis your cells are basically exploding in your muscles,” said Johnson. “It’s like blood poisoning since your body can’t really filter it out.”

Doctors nearly had to cut open the patient’s arms to relieve the swelling — a measure she thought was excessive at the time.

However, the physicians were concerned about long-term kidney damage, which is a common complication of rhabdo that can force people to go on dialysis.

Shockingly, Johnson’s renal organs emerged from the incident unscathed.

“They (doctors) were so surprised,” she said. “They kept telling me ‘we don’t know how you don’t have kidney damage right now with how high your values are.’”

Johnson, who unfortunately did sustain some liver damage, was discharged from the hospital four days after being admitted and said she’s made a “full recovery.”

However, doctors advised the fitness freak to wait a while before working out again and to ease back into exercise rather than engaging in “crazy workouts.”

In light of her life-threatening ordeal, Johnson has called a moratorium on doing the Murph Challenge, noting that she’s more susceptible to rhabdo now because she’s had it before.

“This was a wake-up call for me to chill out a bit,” said the Southerner, who plans to limit her exercise to running, walking, and “more gentle pilates stuff.”

Johnson hopes to use her saga as a cautionary tale on the perils of high-intensity training, explaining: “Working out too much and doing too aggressive of a workout is not good for you and not healthy.”

“You don’t need to be doing super intense stuff all the time,” she added. “It’s okay to do a little bit more of a relaxing workout.”

Named after US Navy SEAL Lt. Michael Murphy who died in Afghanistan in 2005, the Murph Challenge is observed by thousands of CrossFit gyms each year.