NORTH TEXAS (CBSDFW.COM) – MedStar has implemented its extreme weather response as North Texas enters its hottest week of the year, with heat indexes at or above 105 degrees.

This means they will prioritize the response for patients who are outside to limit the patient and responders from exposure to extreme heat.

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MedStar officials said on Tuesday that crews had treated 88 patients in June for heat-related illnesses, and 57 were taken to hospitals. Six were listed in critical condition.

Prolonged or intense exposure to hot temperatures can cause heat-related illnesses such as heat exhaustion and heatstroke.

Heat exhaustion happens when the body loses large amounts of water and salt through excessive sweating, particularly through hard physical labor or exercise. This loss of essential fluids can disturb circulation and interfere with brain function. Symptoms of heat exhaustion may include muscle cramps, paleness, sweating, nausea, and vomiting. Children and the elderly are especially susceptible.

Heatstroke is a life-threatening problem that occurs when the body suffers from long, intense exposure to heat and loses its ability to cool itself. Some of the most common signs of heatstroke include confusion, vomiting, alteration in sweating, hot and flushed skin, rapid heart rate, decreased sweating, shortness of breath, decreased urination, increased body temperature (104 to 106 degrees Fahrenheit), or potentially, even convulsions.

Heatstroke is a medical emergency. If you or someone you know starts experiencing any of the symptoms above, immediately call 911.

While heatstroke and heat exhaustion are common this time of year, they can be easily prevented.

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Hydrate: Drink plenty of water during the day, especially if you are engaged in any strenuous activity. Sports drinks are a good choice if you’re exercising or working in hot conditions, but water is a good way to hydrate as well.

Ventilate: Stay in a place where there is plenty of air circulating to keep your body cool. If you are indoors and don’t have access to air conditioning, open windows and use a fan.

Cover Up: Wear light-colored and loose-fitting clothing to avoid absorbing the sun’s light and trapping heat. Wear a hat to shield yourself from the sun, but once you feel yourself getting warm, remove any items covering your head which can trap heat close to your body.

Limit Activity: Heatstroke can occur in less than an hour when you are participating in strenuous activity during a hot day. If you feel yourself getting hot or light-headed, stop your activity and rest in a cool place out of the sun. Be sure to drink water or a sports drink before, during, and after any strenuous activity.

Check on Loved One’s: The elderly are especially vulnerable to heat related emergencies. Many elderly residents are not aware of how hot it may get in their residence. Call on older friends and family members regularly to assure they are doing OK.

Kids in Hot Cars: So far this summer, MedStar crews have responded to two calls where a child was left in a hot car. Texas leads the nation in child hot car deaths. DO NOT leave children unattended in cars and be sure your vehicles are secured to prevent a curious child from becoming trapped in the car on a hot day. If you find a child unattended in a hot car, alert authorities immediately, and, if necessary, be prepared to take action based on the instructions from the 911 operator.

MedStar also has new ambulances in its fleet that were designed with the Texas heat in mind. The ambulances actually have three air conditioners; one for the cab, and two for the patient/crew compartment (one for the front and one for the rear of the box).

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The National Weather Service in Fort Worth also issued a heat advisory, which is in effect from Tuesday and ends at 7 p.m. Wednesday.