Several people died from cardiac arrests as extreme heat swept across the state this week.

Paramedics were called to 31 cardiac arrests on Thursday. Several of those people died, Ambulance Victoria's state health commander Paul Holmansaid on Friday.

"The vulnerable in our community die as a result of this heat. Heat kills," Mr Holman.

"Vulnerable people are at risk in the heat so check on the elderly, and those with existing health problems."