He issued it in response to five suspected heat illness calls in the Tulsa area. Two of the calls resulted in the transport of patients to hospital. EMSA advises taking several precautions for spending time outdoors over the weekend, as forecasts predict rising temperatures.

• Drink plenty of water or electrolyte replacement drinks several hours before and during long exposure to summer heat.

• Wear loose, light-coloured clothing and a wide-brimmed hat if you work outdoors and take lots of breaks in the shade.

• Avoid drinking alcohol or caffeine.

• Do not limit the use of air conditioning.

• If you don’t have air conditioning, find a cooling station or public space (like libraries or malls) during the day.

• Use the buddy system if you work outdoors and watch older neighbours.

• Keep a cell phone with you at all times when you are outdoors, including walking, daily errands, yard work, or sports and physical activities.

EMSA issues heat alerts when five or more calls for heat-related illnesses occur within 24 hours. EMSA says the heat alert will remain in effect until temperatures and/or the volume of heat-related calls drop significantly.