What symptom might indicate that a patient's normal activity level has changed due to heart failure?

Shortness of breath affecting regular activities is a key symptom that may indicate a change in a patient's normal activity level due to heart failure. This symptom, known as dyspnea, often arises because the heart is unable to pump blood effectively to meet the body’s needs during physical exertion. As heart failure progresses, patients may find themselves becoming increasingly fatigued or breathless with activities that they once performed without difficulty. This change in exercise tolerance is significant, as it reflects a decline in the patient's functional capacity and overall heart health, which are critical indicators in managing heart failure and tailoring appropriate interventions to enhance the patient’s quality of life.