Can fever cause low blood oxygen levels?
Jan 18, 2023
Source: Cainiu Health
Dr. Guo Xiheng
Introduction
Whether fever can cause low blood oxygen depends on the underlying cause of the fever. Although elevated body temperature during fever generally does not affect oxygen exchange, if the fever is caused by pulmonary diseases such as pneumonia, bronchitis, or laryngitis, it may lead to inadequate ventilation and severe decline in lung function, resulting in low blood oxygen levels. Patients who notice a decrease in blood oxygen saturation should seek medical attention promptly.
Fever itself does not necessarily lead to low blood oxygen levels, and the underlying cause of the fever must be considered. While elevated body temperature during fever generally does not affect oxygen exchange, if the fever is caused by pulmonary conditions such as pneumonia, bronchitis, or laryngitis, it may result in inadequate ventilation and severely impaired lung function, leading to decreased blood oxygen levels.
"Blood oxygen" is short for blood oxygen saturation, which refers to the amount of oxygen carried by the blood. Normal blood oxygen saturation in humans typically ranges between 95% and 100%. It tends to be higher—closer to 100%—in younger individuals and slightly lower—around 95%—in older adults. It is important to note that excessively low blood oxygen levels can lead to inadequate oxygen supply to tissues, while overly high levels may accelerate cellular aging.
Simple fever alone does not impair a patient's ability to take in oxygen, so it does not usually cause insufficient oxygen levels in the blood or reduce blood oxygen saturation. However, if the fever results from lung diseases such as pneumonia, bronchitis, lung abscess, or emphysema, respiratory function may be compromised, with impaired ventilation and gas exchange, potentially leading to reduced blood oxygen saturation and even respiratory failure. Additionally, patients with pre-existing cardiovascular diseases may experience poor circulation, preventing oxygen in the blood from being efficiently delivered and utilized by tissues. If such patients develop a fever due to these conditions, it may also contribute to decreased blood oxygen saturation.
When patients notice a drop in their blood oxygen saturation, they should promptly visit a general internal medicine department at a hospital. After undergoing diagnostic tests such as CT scans and electrocardiograms to determine the underlying cause, targeted treatment should be initiated to avoid delays in care. Patients are also advised to avoid strenuous physical activity and receive supplemental oxygen therapy as needed to prevent symptoms such as dizziness and nausea.
