While you’re enjoying yourself outside this summer, remember that heat exhaustion can sneak up on you.

6 signs of dehydration: dry mouth, headache, thirstiness, fatigue, dry lips, lightheadedness

Avoid these heat mistakes:

Reaching for a cold one. Drinking alcoholic or caffeinated drinks can pull water from the body and dehydrate you further. “Drink water or fluids with electrolytes, like a sports drink,” Even says. Also, very cold beverages might make your stomach cramp.

Exercising in the heat. This is not the time to try out a new fitness routine outside. “Either find a way to do the activity in the air conditioning or slowly pace your activity to account for heat,” she says. Make sure to limit your time outside, wear sunscreen, and take a friend and monitor each other’s condition in the heat.

Relying on a fan to cool you off. “Fans blowing dry air are only effective if your skin is wet with sweat,” Even says. “During heat exhaustion or stroke, the body can stop sweating.” Dry fans might push too much warm air on the body, especially in temperatures of upper 90s and higher. Wet the skin by using mist or a cool, wet cloth if you are using a fan to cool yourself.

Warning signs of heat exhaustion include

  • Heavy sweating
  • Paleness
  • Muscle cramps
  • Tiredness and weakness
  • Dizziness or fainting
  • Headache
  • Nausea or vomiting

Seek medical attention if symptoms worsen or last longer than one hour.

Warning signs of heat stroke vary, but may include

  • Extremely high body temperature (above 103° F orally)
  • Red, hot and dry skin (no sweating)
  • Rapid pulse
  • Throbbing headache
  • Dizziness
  • Nausea
  • Confusion
  • Unconsciousness

Heat stroke is life threatening. Call for immediate medical assistance.