# What Hot Weather Does to Your Body

Heat waves stress nearly every system in your body. When temperatures spike, your core body temperature rises, and your cardiovascular system works overtime to pump blood to your skin so you can cool down through sweating. This cooling process requires significant fluid loss, which explains why dehydration happens so quickly in heat.

The heart bears the heaviest load. Cardiologists note that heat-related stress increases blood pressure and forces your heart to work harder, pumping blood away from vital organs toward your skin. People with existing heart conditions, diabetes, or kidney disease face elevated risks during heat waves. Older adults lose some natural ability to regulate body temperature, making them particularly vulnerable.

Heat also affects your brain function. Even mild heat stress impairs cognition, reaction time, and decision-making. When body temperature climbs above 104 degrees Fahrenheit, heat exhaustion sets in, bringing dizziness, nausea, and weakness. Heat stroke, where your body stops sweating and temperature exceeds 104 degrees, becomes a medical emergency requiring immediate cooling.

Certain medications complicate heat tolerance. Diuretics, antihistamines, and stimulants all reduce your body's ability to cool itself effectively. Athletes and outdoor workers face compounded risk because exertion in heat accelerates dangerous temperature rises.

Sweat itself becomes less effective at higher humidity levels. When moisture in the air prevents sweat from evaporating, your body temperature keeps climbing despite increased sweating. This explains why humid heat feels more dangerous than dry heat.

Practical protection matters. Drinking water consistently, avoiding peak heat hours, and wearing light clothing helps maintain stable body temperature. Checking on neighbors, especially those living alone or with chronic illnesses, saves lives during heat waves. Simple shifts like staying indoors with air conditioning and limiting strenuous activity give your cardiovascular system relief