Schneider, 42, who is both director and star of the comedy, was filming at a women's prison when he collapsed Thursday, E! Online reported.
Temperatures in the northern California city have been hovering around the 100 degree mark and firefighters have made several trips to the set to treat crew for heat exhaustion, Zap2it.com reported.
"Big Stan" is about a con man who learns martial arts to defend himself when he is sent to prison for fraud.
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