North region ambulance operations manager Lee Dale has warned that heat-related illnesses can be life threatening.

"Dehydration that is left unmanaged is life threatening," Mr Dale said.

"The moment your body temperature starts to increase, then your body starts to utilise the water and energy that's in it," he said.

He said besides always wearing sunscreen, drinking plenty of water and covering up, there were two musts if playing sport in hot weather.

"Before heading out have a good breakfast and drink plenty of water, that will then pre-top their body," Mr Dale said.

He said fit and healthy adults could last about an hour in the heat, but the young, elderly and people with medical conditions were narrowly reduced to cope.

Mr Dale also said between breaks, make sure to stay under the shade, drink plenty of water, whether they feel they need it or not.

Many sports continue under the heat, but have heat policies.

Whyalla Cricket Association chair John Warner said due to the heat the junior intercity cricket was cancelled at the weekend.

He said Whyalla cricket had a heat policy of 43C for adults and 38C for juniors and if the heat exceeded 40C, overs would be decreased to shorten the game.

The Whyalla Cricket Association also looked to install lights at the cricket grounds, so night games could be played.

Mr Warner said this was a future goal for about 2011, but it was something all the associations should come together and talk about.

"All the associations should come together to see how we can come to common grounds," Mr Warner said.

"We need to work out how we can make it better, the heat's going to be here forever, we can never get rid of it."

Cricket coaches have also been given heat dehydration information.

Under 14's cricket player Luke Schubert said it wasn't good playing under the hot sun, but he always drank plenty of water, wore a hat and sunscreen.