http://www.newsweek.com/heat-stroke-exhaustion-sun-poisoning-symptoms-treatment-historic-1604640

The National Weather Service has urged people to stay safe amid an "historic" heat wave in the western U.S., as excessive heat warnings are in place in most parts of the northwest, the Northern Great Basin, parts of western Nevada and interior California.

Extreme heat can affect different age groups differently, according to the National Weather Service, with those who are pregnant, newborns, children, the elderly and people with chronic illnesses being the most vulnerable. It can cause conditions including heat stroke and heat exhaustion.