Extreme heat can affect anyone, but certain groups are at higher risk, including the elderly, children, and individuals with pre-existing health conditions. Prolonged exposure to high temperatures can lead to heat-related illnesses such as heat exhaustion or heat stroke, which can be life-threatening if not addressed promptly. Pets are also vulnerable and should not be left in hot environments. The CDC emphasizes the importance of recognizing symptoms like dizziness, nausea, or confusion as early warning signs of heat-related health issues.