SAN DIEGO–An excessive heat warning takes effect in the mountains and deserts of San Diego County on Friday. The warning is in effect until 8 p.m. on Sunday. The predicted highs will range from 117 to 122 degrees in the desert with mountain temperatures ranging from 100 to 105 degrees. Heartland Fire & Rescue wants to remind everyone that there are some important things to keep in mind when temperatures rise, especially when it comes to children, the elderly and special needs citizens. Medical experts are advising everyone to slow down when it comes to outdoor activity, especially when it comes to working outdoors and exercising. There are three basic levels to heat illness. One is heat sickness where your body cramps and you experience fatigue. Second is heat exhaustion which includes profuse sweating and dizziness. Third is heat stroke, where you have an extremely high body temperature and hot, dry skin with no sweating. It can be fatal at times. Drink more fluids than normal, even if not thirsty. In the summer, the County designates Cool Zone sites which are air-conditioned settings where seniors and those in need can gather and escape the heat. The Cool Zone sites encourage people to share air conditioning during the heat of the day, lowering individual usage and helping to conserve energy for the whole community. Residents can use officially sanctioned Cool Zones to escape the heat and rest up before going back outside. There are more than 115 locations throughout San Diego County. For a complete listing of Cool Zones, visit www.CoolZones.org, or contact (800) 510-2020 and press ‘6’.