Heart or Lungs? Understanding the Cause of Shortness of Breath.

Shortness of breath is one of the most common reasons patients visit a doctor. But figuring out whether the cause is your heart or your lungs can be tricky. Both systems are closely connected: your heart pumps oxygen-rich blood, and your lungs supply the oxygen. When one isn’t working well, the other feels the strain.

When Shortness of Breath May Be Heart-Related

• Swelling in legs/ankles → Often points to heart failure.

• Worse when lying flat → A classic heart-related symptom (orthopnea).

• Sudden breathlessness at night → Could signal fluid buildup from the heart.

• Associated with chest pain or palpitations → May indicate coronary artery disease or arrhythmia.

  
  

When Shortness of Breath May Be Lung-Related

• Chronic cough (especially with mucus) → Often linked to COPD or asthma.

• Wheezing → A hallmark sign of asthma.

• Triggered by allergens or infections → Suggests lung involvement.

• History of smoking → Raises risk for emphysema and chronic bronchitis.

When It’s Both

Conditions like sleep apnea or pulmonary hypertension can affect both heart and lungs. Patients may feel fatigued, dizzy, and short of breath even with mild activity.

What Tests Help Differentiate?

• EKG/Echocardiogram – Assess heart rhythm and function.

• Pulmonary Function Tests (PFTs) – Measure lung strength and capacity.

• Chest X-ray or CT – Look for lung disease or heart enlargement.

• Blood tests – Check oxygen levels, BNP (for heart failure).

Conclusion

Shortness of breath is not something to ignore. At SD Premier Clinics, our cardiologists and pulmonologists work together to pinpoint the cause — so you get the right care faster.

If you’ve been struggling with shortness of breath, schedule an appointment today. One evaluation could give you peace of mind.