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PATIENT EDUCATION · FATIGUE & REDUCED EXERCISE TOLERANCE

Fatigue and reduced exercise tolerance

Understand low energy and reduced exercise tolerance, possible causes, warning signs, testing, and treatment.

Section 1 of 6 · What is fatigue or reduced exercise tolerance?

← Fatigue and reduced exercise tolerance: the short explanation
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What should I do now?

Call 911

Call 911 for new or unexplained chest pressure that persists or returns, severe trouble breathing, collapse without normal recovery, or sudden face/arm weakness or trouble speaking. Do not drive yourself.

Contact your care team

Contact your care team for persistent or worsening fatigue or a meaningful decline in your usual activity.

Keep your care plan

Record how symptoms affect daily tasks, and review sleep and medications with your clinician.

SECTION 1

What is fatigue or reduced exercise tolerance?

Fatigue is a lack of energy or unusual exhaustion. Reduced exercise tolerance means that activities you could previously manage now require more effort or more rest.

You may notice shorter walking distances, difficulty climbing stairs, or needing breaks during household tasks. Fatigue differs from simply feeling sleepy, although they can overlap.

A persistent or unexplained change should be evaluated. It does not automatically mean heart disease, and it should not simply be dismissed as aging.

Sources & further readingMedlinePlus: FatigueMayo Clinic: Causes of fatigueAmerican Heart Association: Heart failure symptomsAmerican Heart Association: Valve disease symptoms

Updated October 2026. Educational information; your own care plan may differ. Medical illustrations are simplified examples for teaching.