What Happens When Blood-Oxygen Levels Are Too Low?

The cells of the body need a constant supply of oxygen. When oxygen supply is reduced or interrupted, a person may develop hypoxemia, a low level of oxygen in the blood.

Hypoxemia

Hypoxemia can disrupt body function and damage vital tissues. In extreme cases, hypoxemia can be life-threatening.

Symptoms

The first and most common symptom of hypoxemia is shortness of breath. In some cases, symptoms of weakness, fatigue and confusion are also present.

Effects

Low blood-oxygen levels eventually affect every system of the body as organ function deteriorates.

Causes

Common causes of low blood oxygen levels are heart or lung disease, anemia, strenuous exercise, carbon monoxide poisoning, emphysema, pneumonia, shock, shallow breathing, stress and sleep apnea.

Measuring Blood Oxygen

Blood oxygen can be measured by an arterial blood test or by an oximeter, a device that clips onto the finger. At sea level, normal blood oxygen readings are between 95 and 100 percent. Readings under 90 are considered low. At levels below 80 percent, the condition is considered severe.

Treatment

Medical treatment for hypoxemia involves administering oxygen by face mask or mechanical ventilation. Doctors may also recommend regular exercise to strengthen the respiratory muscles and avoiding cigarette smoke.

References

• Fundamentals of Anatomy & Physiology, 4th ed.; Frederic H. Martini, Ph.D.; 1998.
• Anti-Aging Manual: The Encyclopedia of Natural Health; Joseph Marion; 2005.
• Acute Hypoxemic Respiratory Failure (AHRF, ARDS)