As a heat wave rolls across most of the U.S., precautions should be taken to prevent heat-related conditions such as heat stroke, cramps, and sunburn.

The National Weather Service forecasted temperatures reaching higher than 100 degrees stretching from the middle and lower portions of the Mississippi River Valley extending to the mid-Atlantic region and Southeast on Saturday afternoon.

High temperatures coupled with high humidity pushed the heat index to range between 105 and 115 degrees, according to the weather service.

The heat wave puts residents in the affected areas at risk for heat stroke, cramps, sunburn, and dehydration. The elderly, young children, and the sick are most at risk.

Heat stroke is the most serious of these conditions, and it can be deadly if the warning signs are not noticed in time and appropriate medical care is not received.

Fainting is most often the first sign of heat stroke, although a body temperature higher than 105 degrees is also an indication of the illness, according to WebMD.

Other symptoms of heat stroke include throbbing headaches, dizziness, rapid breathing, and seizures.

WebMD offers the following advice on preventing heat stroke:

  • Wear lightweight clothing that is also loose-fitting. Wear a wide-brimmed hat while outside.
  • Use sunscreen with a minimum SPF of 30.
  • Drink extra fluids to prevent dehydration. Water and sports drinks, which are rich in electrolytes, are preferred.
  • Drink 24 ounces of fluid two hours before exercise and drink another 8 ounces for every 20 minutes of physical activity. Follow this advice even if you are not thirsty.
  • If you have an outdoor activity planned, cancel it or reschedule the activity for the early morning or sunset, when temperatures are not as intense
  • Pay attention to the color of your urine. A darker color is an indication of dehydration.

The heat wave may also be responsible for heat cramps, which are painful, brief muscle cramps that happen during exercise or work in a hot environment, according to emedicinehealth.com.

People are most at risk for heat cramps when they work or are participate in activities in a hot environment or they sweat a lot during exercise and don't replenish their fluids.

The elderly, infants, young children, and people who don't have air conditioning are most at risk of developing heat cramps.

Symptoms of heat cramps are spasms that are painful, involuntary, brief, intermittent, and resolve on their own.

While heat cramps cause sufferers a great deal of pain, the condition is not usually a medical emergency. However, heat cramps can be a sign of heat stroke.

Sunburn is another condition to be wary of during a heat wave. Taking a few precautions will keep sunburn at bay.

The best ways to prevent sunburn is wearing a sunscreen that has an SPF of 15 or greater, according to the Mayo Clinic, and applying it liberally on your body. Make sure to reapply sunscreen after a dip in the pool or after sweating.

Avoiding the sun is the surest way to prevent sunburn, but if you must catch some rays, the best time for your health to do so is after 4 p.m. or before 10 a.m. The sun's rays are strongest between 10 a.m. and 4 p.m., the Mayo Clinic notes.

Most sunburns are not medical emergencies, although you'll want to call your doctor if you experience increased pain, swelling, pus, and red streaks, as this may indicate your sunburn has resulted in an infection. You should also call your physician if you have a fever accompanied by pain, headache, confusion, nausea, or chills. Other reasons to call a doctor include the development of blisters or your sunburn does not respond to home care.