G20 leaders have been encouraged to check their pee is straw-coloured so they know they are drinking enough water.
Queensland Health chief health officer Jeannette Young's advice comes as temperatures are set to reach more than 40 degrees.
Dr Young also suggested leaders and delegates stay out of the scorching sun.
She said the elderly, infants, overweight and obese people, pregnant and breastfeeding women and people with some pre-existing health conditions were more prone to heat-related illnesses.
"Heat-related illness occurs when the body overheats and cannot cool itself down," Dr Young said.
"The effects of overheating on the body can vary from heat rash and cramps through to heat exhaustion or heat stroke."
- APN NEWSDESK
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