Five Tufts University men's lacrosse players are still hospitalized after a workout on Monday, led by a former Navy SEAL trainee.

The session, involving 50 athletes, resulted in 12 players being diagnosed with rhabdomyolysis, a potentially life-threatening condition caused by extreme overexertion.

According to the Cleveland Clinic, rhabdo occurs when muscle tissue breaks down, releasing toxins into the bloodstream that can cause kidney damage. Seven players were treated in the emergency room and released, while five remain hospitalized, CBS News reported.

"It's very unusual to see that many people being hospitalized all at once with this condition, particularly young men who are presumably very physically fit," Dr. Shruti Gupta, of Brigham and Women's Hospital in Boston, told the outlet.

In a statement to The Tufts Daily, the school's student-run newspaper, Tufts' executive director of media relations Patrick Collins said, "Both the number of confirmed cases and the number of those hospitalized could change. Our thoughts are with the players and their families, and we are hoping for their quick return to good health under the care of local medical experts."

The university has suspended all lacrosse team practices until the athletes can be medically cleared, and initiated an independent investigation into the incident.