An absence of enough oxygen in the blood to sustain bodily functions.


Don't smoke, and avoid secondhand smoke.

When to seek immediate medical care

See a doctor immediately if:

  • Sudden and severe shortness of breath
  • Rapid heartbeat
  • Persistent cough and fluid retention

When to make a doctor's appointment

Make an appointment to see a doctor if:

  • Shortness of breath at rest or after slight activity
  • Shortness of breath that doesn't get better quickly after activity
  • Shortness of breath or a sense of choking when waking up

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