Fatigue and reduced exercise tolerance, made clear.

A new loss of energy or drop in walking distance deserves attention. Causes include sleep problems, anemia, medicines, atrial fibrillation (AFib), and other heart or lung conditions. It should not simply be dismissed as aging.

Heart failure can reduce stamina with either a reduced or preserved ejection fraction. AFib can also cause fatigue and reduced exercise tolerance, even without a racing pulse.

Your clinician starts with the pattern of symptoms, an examination, and medicine review. Blood tests, an EKG, or an echocardiogram may be appropriate.

Testing is selected for your situation; fatigue alone does not establish a heart diagnosis.

Note which activities have become harder, when you need rest, sleep quality, and any breathlessness, swelling, or palpitations.

Bring a medicine list and a few concrete examples of what has changed.