Several factors are needed to continuously supply the cells and tissues in your body with oxygen:

• There must be enough oxygen in the air you are breathing
• Your lungs must be able to inhale the oxygen-containing air — and exhale carbon dioxide
• Your bloodstream must be able to circulate blood to your lungs, take up the oxygen and carry it throughout your body

A problem with any of these factors — for example, high altitude, asthma or heart disease — might result in hypoxemia, particularly under more extreme conditions, such as exercise or illness. When your blood oxygen falls below a certain level, you might experience shortness of breath, headache, and confusion or restlessness.

Common causes of hypoxemia include:

1. Anemia
2. ARDS (Acute respiratory distress syndrome)
3. Asthma
4. Congenital heart defects in children
5. Congenital heart disease in adults
6. COPD (chronic obstructive pulmonary disease)
7. Emphysema
8. Interstitial lung disease
9. Medications, such as certain narcotics and anesthetics, that depress breathing
10. Pneumonia
11. Pneumothorax (collapsed lung)
12. Pulmonary edema (excess fluid in the lungs)
13. Pulmonary embolism (blood clot in an artery in the lung)
14. Pulmonary fibrosis (scarred and damaged lungs)
15. Sleep apnea

• Definition
• When to see a doctor

Jan. 11, 2018