Most people experience fatigue from time to time, whether due to stress, poor sleep, or a brief illness. But experts warn that if you feel exhausted day after day—with no clear explanation—it may be a sign of something far more serious.

Professor Julia Newton, a consultant geriatrician speaking to the British Heart Foundation, explains that medical fatigue goes beyond ordinary tiredness. She describes it as an overwhelming loss of energy, “like starting the day with a full battery that drains far too quickly.” Many people also report waking up just as tired as when they went to bed.

Doctors say this lingering fatigue could point to heart failure, a condition affecting nearly 900,000 people in the UK. Because symptoms often develop slowly, many people don’t recognize them until significant damage has occurred.

Cardiologist Dr. James Wetherby calls heart failure a “silent danger,” noting that tiredness is one of the earliest and most frequently overlooked warning signs. When the heart becomes too weak or stiff to pump blood effectively, the body’s tissues receive less oxygen—leading to constant exhaustion.

Other Symptoms to Watch For

Signs may include shortness of breath, swollen legs or feet, unexplained weight gain, dizziness, a persistent cough, bloating, loss of appetite, or a rapid heartbeat.

Protecting Your Heart Health

Experts stress the importance of early diagnosis. The NHS recommends lifestyle measures such as regular exercise, a balanced diet, maintaining a healthy weight, and quitting smoking. Treatments may include medication, implanted devices, or surgical procedures, depending on severity.

If persistent fatigue is disrupting your daily life, doctors urge you to seek medical advice promptly.