 Valley Health System ER physician Grant Lipman says the body's inability to cool can lead to heat stress and heat stroke. When people walk out into these really intense temperatures, one of the body's reaction is that you have a shunting of blood from the core to the periphery to try to cool down. County officials say the need now is to raise awareness in older residents or those with small children. Jesse Gary with Fox 2 San Francisco. America's listening to Fox News.