Know the difference between heat exhaustion and heat stroke and when to seek emergency care

The warning signs of heat exhaustion include fatigue, extreme thirst, nausea, headache, shortness of breath, rapid breathing, muscle cramping and feeling dizzy or lightheaded.

Heatstroke is a much more serious emergency. The warning signs include all the above but also may include a strong, rapid heartbeat, confusion, vomiting, seizures, slurred speech, or passing out. Watch for a body temperature that exceeds 103 degrees F.

The first step to help anyone who exhibits symptoms of heat exhaustion or heatstroke is to get them to immediately stop what they are doing and rest somewhere out of the sun, Dr. Matt Leonard, attending emergency physician at Suburban Hospital, Johns Hopkins School of Medicine, told NPR.

Take steps immediately to cool the person who's overheated: Get them into air conditioning if possible, or at least shade with a fan or breeze. Mist them with a spray bottle, for example, or pour water over their head. The most important places to cool are the head and face, the armpits and the groin, he says.

If symptoms point to heatstroke (watch especially for neurological symptoms like confusion), get them to an emergency room right away