From heat cramps to heat exhaustion to heat stroke, here's a look at preventable illnesses, and how you can keep cool and healthy. Here's what to know. What is extreme heat?

Heat-related illnesses can affect anyone. Officials say prolonged exposure to extreme heat without relief can cause health issues ranging from mild to severe and, in some cases, even death.

Decreased urine output. Heat cramps. Heat cramps Heat cramps arise from excessive sweating and a loss of water and salt; low salt levels in the muscles can result in muscle cramps.

Heat exhaustion: A person who has heat exhaustion will sweat heavily, be tired, cool and clammy, have a weak, fast pulse, have muscle cramps, dizziness, nausea, headaches and may faint.