Severe heat may cause illness or even death. Air-conditioning is the number one protective factor against heat-related illness and death. Since heat-related illness and deaths are preventable, people need to be aware of who is at greatest risk and what actions can be taken to prevent a heat-related illness or death. Those who are at highest risk include people 65 and older, children younger than two, and people with chronic diseases or mental illness. However, even young and healthy individuals can get sick from the heat if they participate in strenuous physical activities during hot weather. When temperatures rise to extreme highs, reduce risks by taking the following precautions.