Heat is the word of the day in Arizona — extreme heat, to be more exact.

The National Weather Service extended its "excessive heat warning" through Friday as high temperatures are forecast to hit 115 or above all week. Monday should be the 18th straight day at 110 or more with 116 the forecast high. 

And all of this affects public health.

From rising concerns about our region’s growing homeless population to guidance about how to keep safe outdoors, the heat is at the top of everyone’s minds.

The Show spoke with Will Humble, executive director for the Arizona Public Health Association, about how extreme heat changes the game.