Stress is defined as the body's reaction to any demand placed on it. Prolonged stress can lead to strain and illness over time. Stressors are the causes of stress and can be external like work demands or internal like negative self-talk. The stages of stress are alarm, resistance, and exhaustion. Chronic stress is associated with increased risk of heart disease, immune system problems, and other illnesses. Learning to manage stress through relaxation, social support, and addressing stressors can help prevent negative health impacts.