What is rhabdomyolysis? The muscle condition her father says killed NYC Marathon runner Rachel Apa, 24

TCS New York City Marathon was the scene of tragedy on Sunday when a 24-year-old woman suddenly died of a muscle condition - despite being in ‘perfect health’ according to her father.

According to organisers, the New York Road Runners (NYRR), the woman, identified as Rachel Apa, collapsed near mile 24 of the run – just over two miles from the end of her first marathon, which she ran for the Parkinson’s Foundation in memory of her grandfather who died in 2022, according to the New York Times.

She was given CPR by a bystander and then by event medical staff, who used a defibrillator, NYRR said, before being taken to hospital by ambulance, where she died.

High-intensity physical exertion can be a cause of the muscle condition (Theodore Parisienne / New York Daily News via Getty Images)

NYRR said in a statement to ABC News: “We are deeply saddened by Rachel’s passing following running in Sunday’s race.

"Our thoughts and sincere sympathies are with her family, friends, and the entire running community.”

Apa’s father told the New York Times, she died of a condition called rhabdomyolysis, which can be life-threatening during physical activity.

Steve Apa told The Times, ‘It’s unfathomable’, before describing her as being in ‘perfect health, perfect shape, 24 years old’ until she collapsed and died.

What’s rhabdomyolysis?

The condition, sometimes called ‘rhabdo’, includes when injury to muscle membrane leads to the release of electrolytes and proteins into the bloodstream during physical activity, which can become life threatening, according to the North Bristol NHS Trust.

This can lead to seizures, heart arrhythmias, nausea, vomiting, organ damage or death, states the Centers for Disease Control and Prevention.

Can anyone develop rhabdomyolysis?

Anyone can develop rhabdomyolysis, states the NHS, but people who have been immobile for a long time, for example after taking drugs or alcohol can be at risk.

People with sepsis and those who have undergone intensive exercise when accompanied by heat exhaustion can also be prone to the condition.

Rachel was healthy before she died according to her father (Instagram/Isabella P)

Some hereditary conditions and snake or insect venom can also increase the risks of developing the conditions, states the NHS.

The CDC says people exposed to heat such as first responders, outdoor workers or those who suffer accidents that expose them to risk factors can be in danger of rhabdomyolysis.

Symptoms of rhabdomyolysis?

The CDC lists symptoms that may seem like heat-related sicknesses such as cramps, exhaustion and nausea.

Other symptoms can include muscle pain, joint pain, fatigue, weakness, light-headedness, passing dark urine, intolerance to exercise, inability to concentrate or complete tasks that can normally be completed.

Secondary conditions can include seizures, low blood pressure, renal failure and more, according to MedlinePlus.

Rachel was a keen runner (Michelle Apa)

Can rhabdomyolysis be treated?

Rhabdomyolysis needs urgent medical attention, and the CDC advises anyone with symptoms to seek help immediately.

Treatment takes place in hospital and depends on how much muscle and organ damage has occurred.

Doctors typically give large amounts of fluid through a drip to protect the kidneys and flush out substances released from damaged muscle, and they monitor blood levels. In severe cases, patients may need kidney dialysis or intensive care.

If you’re worried about symptoms such as severe muscle pain or weakness, or very dark urine, contact a doctor or call NHS 111 (or 999 in an emergency).