Pushing too hard at the gym can lead to a condition called exertional rhabdomyolysis, which has seen an increase in diagnoses as high-intensity workouts become more popular. In January 2025, a first-time attendee at a bootcamp class experienced this danger after participating in a series of floor exercises, including lateral shuffle push-ups. Encouraged by a “militant” instructor and booming music, the participant pushed past exhaustion, only to find the next day that their arms were stiff and incapacitated. After discovering symptoms like extreme pain, weakness, and dark urine, they went to the emergency room, where their creatine kinase (CK) levels measured a staggering 57,000 units per liter, necessitating a seven-day hospital stay.
Doctors diagnose this condition when muscle enzyme levels in the blood spike, typically starting around 1,000 units per liter, though Dr. Barry Boden, an orthopaedic surgeon at The Orthopaedic Center in Maryland, notes that some guidelines suggest diagnosis and inpatient care for levels as high as 10,000 units. When muscle cells are damaged by extreme effort, they release contents like myoglobin into the bloodstream, which can overwhelm and damage the kidneys. While some cases are mild, researchers estimate that 10% of patients develop acute kidney injury, and the condition is potentially fatal in very rare cases.
Experts indicate that while data is difficult to track because no single organization collects it, Dr. Boden authored a study estimating more than 40,000 exertional rhabdomyolysis cases were seen in US hospitals between 2000 and 2019. Reports indicate the condition is rising, with increased hospital records in Norway, Australia, and the US between the 2000s and 2010s, as well as a recent surge in a Canadian province. Because symptoms like muscle pain and weakness closely resemble normal delayed onset muscle soreness, many cases remain under-reported.
The risk is highest when individuals engage in intense, unfamiliar movements. Dr. Petr Schlegel, a CrossFit trainer and professor, identifies high-intensity exercise that combines strength and endurance as having the greatest potential for injury. Dr. Bryant Walrod, a sports medicine physician, points to “hyperintense” workouts targeting large muscle groups as a major risk factor, especially when volume is extreme, such as doing hundreds of push-ups or squats. In 2024, the National Federation of State High School Associations identified push-ups as the number one cause of the condition, a concern underscored by a lawsuit filed in April by Texas families after 20 children were hospitalized following a high-volume push-up session.
Prevention has centered on consistent guidance since the 1960s: vary exercises to avoid overloading specific muscle groups, incorporate rest, and build intensity gradually. While some organizations like CrossFit have updated their curriculum to include prevention, experts note that not all fitness instructors are adequately trained in physiology. For the survivor of this condition, recovery has been a long process involving low-impact exercise and learning to advocate for themselves by pausing when necessary. Experts emphasize that because no universal metric for safe intensity exists, individuals must listen to their own bodies and stop immediately if they encounter unusual pain, as prioritizing health over fitness culture’s “no pain, no gain” mentality is essential for safety.
