Causes

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:

• Anemia
• ARDS (Acute respiratory distress syndrome)
• Asthma
• Congenital heart defects in children
• Congenital heart disease in adults
• COPD (chronic obstructive pulmonary disease) exacerbation — worsening of symptoms
• Emphysema
• Interstitial lung disease
• Medications, such as certain narcotics and anesthetics, that depress breathing
• Pneumonia
• Pneumothorax (collapsed lung)
• Pulmonary edema (excess fluid in the lungs)
• Pulmonary embolism (blood clot in an artery in the lung)
• Pulmonary fibrosis (scarred and damaged lungs)
• Sleep apnea