The 26-year-old martial artist was said to have rushed to the hospital following a K-1 contest at the Central Hall in Southampton on Saturday night.
She passed away a day after failing to respond to treatment and the Hampshire Police confirmed her death to BBC, adding that they have commenced investigations into her death.
After passing away, Stonehenge CrossFit, where the fitness fanatic trained for over three years, paid tribute on their Facebook page.
Their post read: “Saeideh Aletaha was just 26 when she died on Sunday.
“She took part in competitions, was friends with all she met, had time for everybody and was a tireless worker when she trained.
“As she lay in the hospital, on Sunday, more than 30 members visited to say goodbye to their friend.
Some couldn’t bring themselves to say a final farewell.