Heart-Related Fatigue

Heart-related fatigue is a term for feeling tired, weak, or worn out quickly because the heart and blood vessels cannot deliver enough blood to meet the body's needs, especially during activity. Fatigue is not a diagnosis but a symptom that can have many causes. This page helps you recognize when tiredness should be checked by a doctor, without replacing a medical examination.

Features of Heart-Related Fatigue

Heart-related fatigue usually appears or gets worse during activity, such as climbing stairs, walking, or carrying groceries, and often comes with shortness of breath, palpitations, or swollen legs. Your ability to be active declines gradually compared with a few months earlier. In heart failure, fatigue often comes with shortness of breath when lying down and rapid weight gain from fluid retention; this is covered on the Heart Failure page. In coronary artery disease, especially in women, older adults, and people with diabetes, fatigue or shortness of breath during activity can be a sign of reduced blood flow to the heart muscle, even without chest pain. Sudden, unusual fatigue with a cold sweat or nausea can be a sign of a heart attack and needs urgent help.

Causes Inside and Outside the Heart

Heart-related causes include heart failure, coronary artery disease, valve disease, rhythm disorders that are too slow, too fast, or irregular, and cardiomyopathy. Certain heart medicines, such as beta blockers or diuretics, can also make you feel weak; do not stop them on your own, and talk to your doctor. Outside the heart, fatigue often comes from a low blood count (anemia), thyroid disorders, diabetes, kidney disease, sleep disorders such as sleep apnea, infection, depression, or anxiety. Sometimes several causes occur together.

Why the Cause Needs to Be Found

Tiredness is very common and often improves with enough sleep and a healthy lifestyle. However, new fatigue that lasts more than a few weeks, or that comes with heart symptoms, should be checked. Recognizing the cause early allows the right treatment, such as heart failure medicines that improve exercise capacity, treatment of iron deficiency, or management of rhythm disorders. Shortness of breath that comes with fatigue is covered on the Shortness of Breath page.

The doctor starts by asking when your tiredness began, whether it appears during activity or throughout the day, and about your sleep, mood, weight, and the medicines you take. The physical examination looks for signs such as abnormal blood pressure and pulse, a heart murmur, sounds of fluid in the lungs, or swollen legs. Initial blood tests usually include a complete blood count to look for anemia, iron stores, blood sugar, kidney function, electrolytes, and thyroid function. If a heart cause is suspected, an NT-proBNP test helps assess the likelihood of heart failure, an ECG looks for rhythm disorders or signs of a previous heart attack, and echocardiography assesses the heart's pumping and valves. A treadmill exercise test assesses how the heart responds as the workload increases, while a rhythm recording of 24 hours or longer is used if fatigue comes with palpitations or dizziness. If no heart cause is found, the doctor directs testing toward other causes.

Occasional tiredness after a lack of sleep or hard work usually improves with rest. See a doctor if new fatigue lasts more than two to three weeks, keeps getting worse, or comes with any of the following. Go to the emergency room right away if sudden fatigue comes with chest pain, severe shortness of breath, or fainting.

• Tiring quickly or getting short of breath during activities that used to feel easy
• Swollen legs or rapid weight gain over a few days
• Palpitations, or a heartbeat that is too slow or irregular
• Dizziness or nearly fainting during activity
• Weakness after starting a new medicine
• You have high blood pressure, diabetes, or heart disease and are tiring more quickly