Clark was driven to an urgent care center Wednesday night after he began having chest pains and numbness in his left arm while working out at a gym, TMZ reported Sunday.
He was taken to a hospital by ambulance, where doctors put in a stent after finding a blood clot.
"American Gladiators" aired from 1989 to 1996 and was revived in 2010. Clark, who has also appeared in movies and on television as an actor, was "Nitro" in the original and a producer of the revived show.
Clark. 49, told TMZ steroid use was seen as normal in his "Nitro" years.
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