The heat wave currently gripping the central United States and parts of Canada has pushed the temperature over 37 Celsius (100 degrees Fahrenheit), and America's Centers for Disease Control and Prevention (CDC) has issued a warning on keeping cool, particularly when playing outdoor sports.

Here is what you need to know to keep cool and stay safe in hot weather. The CDC recommends that those who spend time in the heat take frequent rest breaks, drink plenty of fluids, and limit activity on hot or very humid days.

On July 29, WebMD News advised to know the symptoms and signs of heat illness, which include heat rash, muscle cramping, heavy sweating, nausea and vomiting, high body temperature, weakness, and fainting.

Other tips for staying safe in hot weather, from the CDC:

• Keep cool. If you don't have an air conditioner, visit air-conditioned public facilities such as libraries and shopping malls.
• Wear lightweight, light-colored, loose-fitting clothing.
• Drink chilled non-alcoholic beverages and increase your fluid intake regardless of your activity level.
• On hot days, exercise indoors, or exercise during cooler times of the day, such as early in the morning.

More hot weather tips: