The death of a 24-year-old first-time marathon runner has put a rare but dangerous condition called rhabdomyolysis in the headlines. Rachel Apa, a former Division I field hockey player at Bucknell University, collapsed near mile 24 in New York City's Central Park on Sunday, November 1, 2026 — about two miles short of the finish line. Her father, Stephen Apa, told The New York Times that the cause was rhabdomyolysis, a muscle condition that can be triggered by extreme exertion. Apa, a native of Lewisberry, Pennsylvania, was running to honor her grandfather, who died of Parkinson's disease in 2022, and to raise money to help others battling the illness. Here is what rhabdomyolysis is, why it can become life-threatening, and how to recognize and reduce your risk.

What Is Rhabdomyolysis?

Rhabdomyolysis (pronounced "rab-doe-my-OL-ih-sis") is a serious condition in which skeletal muscle tissue breaks down rapidly. When muscle cells are damaged, they rupture and spill their contents — including a protein called myoglobin, the enzyme creatine kinase (CK), and electrolytes such as potassium — directly into the bloodstream. In a healthy body, those substances stay safely locked inside muscle cells. Once released, they can overwhelm the kidneys and other organs.

The name comes from three Greek roots: "rhabdo" (rod-shaped, referring to skeletal muscle), "myo" (muscle), and "lysis" (breakdown). Although it is considered rare, it is a well-known medical emergency that sports-medicine teams and emergency rooms watch for closely.

How Rhabdomyolysis Damages the Body

The most dangerous substance released by damaged muscles is myoglobin, an iron-containing protein that normally stores oxygen inside muscle cells. When large amounts of myoglobin enter the bloodstream, the kidneys must work hard to filter it out. Myoglobin can clog the kidneys' tiny filtering tubes and, at high concentrations, is directly toxic to kidney tissue. Left untreated, this can lead to acute kidney injury or even kidney failure.

At the same time, the sudden release of potassium from ruptured cells can trigger dangerous — and potentially fatal — heart-rhythm problems. The flood of muscle contents can also cause fluid shifts, inflammation, and severe swelling inside the affected limbs, a complication known as compartment syndrome.

Rhabdomyolysis Symptoms to Watch For

Doctors often describe a "classic triad" of rhabdomyolysis symptoms: muscle pain, muscle weakness, and dark, tea-colored or cola-colored urine. However, according to the Merck Manual, all three signs appear together in fewer than 10 percent of patients, which is one reason the condition can be easy to miss early on.

Other warning signs include:

  • Severe or unusual muscle pain and soreness, often out of proportion to a workout
  • Muscle swelling, tenderness, or stiffness
  • Dark, brownish, or reddish urine (caused by myoglobin, not blood)
  • Weakness or trouble moving the affected muscles
  • Fatigue, nausea, vomiting, or confusion
  • Decreased urination

Dark urine is one of the clearest red flags. It is not blood but rather the myoglobin released from dying muscle fibers being excreted by the kidneys. Anyone who develops these symptoms — especially after intense or unaccustomed exercise — should seek medical care promptly.

What Causes Rhabdomyolysis?

Rhabdomyolysis has many triggers, which generally fall into a few broad categories:

  • Extreme or unaccustomed exercise: The most common cause among otherwise healthy young people — and the one tied to Rachel Apa's case. Intense workouts, particularly in the heat or far beyond a person's usual training, can damage muscle cells faster than the body can repair them. This form is sometimes called exertional rhabdomyolysis. Endurance athletes and so-called "weekend warriors" who suddenly ramp up their effort are at particular risk.
  • Trauma and crush injuries: Car accidents, falls, and crush injuries from collapsed structures can physically destroy muscle tissue.
  • Heat stroke and severe dehydration: Overheating accelerates muscle breakdown and makes the kidneys more vulnerable.
  • Drugs, alcohol, and medications: Alcohol, cocaine, and certain medications — including statins used to lower cholesterol — can trigger muscle breakdown, especially at high doses or in people with additional risk factors.
  • Other causes: Seizures, prolonged immobilization (such as lying unconscious in one position), severe infections, and electrical injuries can all lead to rhabdomyolysis.

How Rhabdomyolysis Is Diagnosed and Treated

Doctors diagnose rhabdomyolysis mainly with a blood test that measures creatine kinase (CK), an enzyme that leaks from damaged muscle. In rhabdomyolysis, CK levels are markedly elevated — often many times higher than normal. Urine tests can detect myoglobin, and blood tests also check kidney function and electrolyte levels such as potassium.

The cornerstone of treatment is aggressive hydration with intravenous (IV) fluids. Pushing large volumes of fluid through the body helps flush myoglobin and other muscle contents out of the kidneys, protecting them from damage. Medical teams also closely monitor and correct electrolyte imbalances and watch for complications such as irregular heart rhythms and compartment syndrome. If the kidneys do fail, temporary dialysis can filter the blood until they recover. With prompt treatment, most people recover, though some experience lingering muscle weakness for several weeks.

How to Prevent Rhabdomyolysis

For athletes and casual exercisers, the reassuring news is that exertional rhabdomyolysis is largely preventable. Experts, including those at Cleveland Clinic, recommend several commonsense strategies:

  • Build up gradually: Increase distance, intensity, and weight slowly over weeks rather than all at once, and avoid sudden spikes in training volume.
  • Stay hydrated: Drink enough water before, during, and after exercise — and more when it is hot.
  • Avoid overheating: Take breaks in the shade, wear breathable clothing, and let your body acclimatize to hot weather gradually.
  • Rest and recover: Give muscles time to repair between hard sessions, and do not push through severe pain.
  • Be cautious with pain relievers: Avoid non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen around intense training or competition, because they can add stress to the kidneys.
  • Do not train when unwell or severely dehydrated: Illness, fever, and dehydration raise the risk of muscle breakdown.

Key Takeaways

  • Rhabdomyolysis is a rare but serious condition in which damaged muscles break down and leak myoglobin, creatine kinase, and potassium into the bloodstream.
  • The main danger is acute kidney injury caused by myoglobin, along with heart-rhythm problems from high potassium levels.
  • Classic warning signs are muscle pain, weakness, and dark, tea-colored urine — though they do not always appear together.
  • Extreme or unaccustomed exercise, especially in the heat, is a leading cause among otherwise healthy people.
  • Treatment centers on IV fluids to protect the kidneys; prevention focuses on gradual training, hydration, and avoiding overheating.