An exercise stress test is a medical procedure used to assess how well the heart functions during physical activity. During the test, a patient typically walks on a treadmill or pedals a stationary bike while their heart rate, blood pressure, and electrocardiogram (ECG) are monitored. This helps doctors evaluate the heart's response to increased workload and identify any potential issues. These tests are often used to diagnose conditions such as coronary artery disease or to determine the effectiveness of heart treatments. They can also help in developing a safe exercise plan for patients with existing heart conditions.