According to Wikipedia, the phrase "dog days of summer" refers to the hottest, most sultry days, usually between July and September, depending on the region. They describe a time that is "very hot and stagnant, or marked by dull lack of progress."
(Hmmmmmm, that could describe LOTS of my days in any month!) The term "dog days" was used by the Greeks and ancient Romans (days of the dogs), after Sirius, the "dog star". The ancients believed Sirius was the cause of the hot, sultry weather, and would even sacrifice a brown dog at the beginning of this period to appease the star.
Popularly believed to be an evil time "when the seas boiled, wine turned sour, dogs grew mad, and all creatures became languid, causing to man burning fevers, hysterics, and phrensies" - Brady’s Clavis Calendarium,
Extreme heat can cause heat-related illnesses, or even death. Normally, we cool our bodies down by sweating, but in very extreme conditions, our bodies can lose the ability to regulate our temperature causing heat stroke. Heat exhaustion is a milder condition and occurs with prolonged exposure to heat and not enough body fluid. This condition often effects outdoor workers, the elderly, and people with high blood pressure.
Here are some tips to stay cool this summer:
Drink lots of water and non-alcoholic liquids. Don't wait until you are very thirsty. By then you are already dehydrating!
Pace yourself when working or playing outdoors. Find shade!
Wear light weight clothing, sunscreen and a hat!
Seek moderate air conditioning.
Take cooler showers of spray yourself with cool water.
Use common sense! Don't leave children or pets in a hot car. Use a windsheild protective screen, and be careful when getting into a hot car. Metal seat belt clasps become "branding irons". Crack your window when parking in the sun. (I know of two windsheilds that cracked shattered while parked last month in the heat in Palm Desert.)
My addition: eat more gelato!