Article content The duration of this heatwave is concerning because with temperatures cooling at night to levels that would be considered a hot daytime high, the record-breaking heat will increase the potential for related illnesses, Environment Canada warned. “Drink plenty of water even before you feel thirsty, and stay in a cool place,” the federal weather agency said. “Check on older family, friends and neighbours. Make sure they are cool and drinking water.” Never leave children, elderly people or pets inside a parked vehicle, and outdoor workers should take regularly scheduled breaks in a cool place. Symptoms of heat illness include: Dizziness/fainting; nausea/vomiting; rapid breathing and heartbeat; extreme thirst; decreased urination with unusually dark urine.