An NYC Marathon runner died suddenly at 24. Her family says the cause was rhabdomyolysis, a rare risk even for fit athletes.

A woman died after collapsing at the New York City Marathon from a rare side effect of hard exercise called rhabdomyolysis. kena betancur / AFP via Getty Images

A 24-year-old woman who died after the New York City Marathon on Sunday was suffering from a rare side effect of exercise called rhabdomyolysis, her family said.

Rachel Apa, an experienced D1 field hockey athlete who spent months training for the race, collapsed near mile 24 in Central Park and was taken by ambulance to the hospital, her father told The New York Times .

The New York Road Runners, the group that organizes the marathon, and Apa's family did not immediately respond to a request for comment from Business Insider.

Rhabdomyolysis, known as rhabdo, is a risk of extensive strenuous exercise caused by muscle tissue breaking down and overloading the kidneys.

Without prompt medical treatment, it can be…