# What Does Hot Weather Do to the Body?
Extreme heat stresses the body's cooling system in ways most people underestimate. When temperatures spike, your core body temperature rises, forcing your cardiovascular system to work overtime. Blood vessels dilate to push heat to the skin's surface, your heart rate accelerates, and sweat production increases. This physiological cascade drains fluids and electrolytes rapidly.
Heat exhaustion emerges when the body loses too much water and salt. Symptoms include heavy sweating, weakness, dizziness, and nausea. Heat stroke, the more dangerous outcome, occurs when core temperature exceeds 104 degrees Fahrenheit. At that threshold, the body's cooling mechanisms fail entirely. Confusion, loss of consciousness, and organ damage follow quickly. Heat stroke kills without immediate medical intervention.
Vulnerability clusters in specific populations. Older adults struggle to regulate temperature as aging impairs sweat response and thirst sensation. Young children lack developed thermoregulation. People with chronic conditions like heart disease or diabetes face compounded risk. Medications including diuretics and stimulants impede cooling. Low income, limited air conditioning access, and outdoor work amplitudes exposure hazards for millions.
The heat also worsens existing health conditions. Asthma flares during heat waves. Mental health deteriorates alongside physical strain. Dehydration concentrates blood, increasing clotting risk and stroke danger. Athletes and outdoor laborers face collapse when pushing exertion during peak temperatures.
Prevention centers on hydration, shade-seeking, and recognizing early warning signs. Wearing light clothing, avoiding peak sun hours, and checking on vulnerable neighbors saves lives. Public health systems activate cooling centers during dangerous heat events. Climate change makes these episodes more frequent and intense, raising the stakes for population health planning.