What Is a Normal SpO₂ Level? When Should You Be Concerned?
SpO₂ (Saturation of Peripheral Oxygen) measures the percentage of hemoglobin in blood that is carrying oxygen. It directly reflects how well the lungs supply oxygen to the body. Monitoring SpO₂ during sleep is especially important for detecting sleep apnea.
Reference ranges
* Reference values only. Consult a doctor for personalized advice.
Low SpO₂ during sleep — What does it mean?
SpO₂ dropping below 90% during sleep can indicate sleep apnea — a condition where the airway is intermittently blocked during the night. This is a serious health issue affecting sleep quality, cardiovascular health, and stroke risk if left untreated.
What causes low SpO₂?
Common causes include: lung diseases (asthma, COPD, pneumonia), anemia, high altitude (thinner air), sleep apnea, and certain heart conditions. Long-term smoking progressively reduces the blood's oxygen-carrying capacity.
Why monitor SpO₂ during sleep?
Many people with sleep apnea are unaware of their condition because symptoms occur while asleep. Overnight SpO₂ monitoring can detect abnormal oxygen drops — providing data to discuss with a doctor about whether further testing is needed.
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