Apple Watch adds blood oxygen saturation detection. What is blood oxygen detection? Who needs the test?

Yesterday's Apple press conference brought out another black technology. The new Apple Watch added blood oxygen saturation detection. This means that blood oxygen saturation, which represents the body's oxygen supply capacity indicator, can be detected through a small watch. This new highlight has attracted widespread attention.

What is blood oxygen saturation?

Oxygen is an essential substance for human survival. When oxygen is inhaled into the human body, it combines with hemoglobin in red blood cells and is then carried to various parts of the body for substance exchange, bringing "nutrients" to cells while taking away "waste" from the cells, so that our cells can continue to complete their missions.

However, not all hemoglobin can combine with oxygen smoothly. There are always some hemoglobin that cannot carry oxygen for various reasons. Blood oxygen saturation is a measure of the proportion of hemoglobin that carries oxygen. In other words, it is a measure of the oxygen-carrying capacity of hemoglobin.

What is the normal range of blood oxygen saturation?

Since blood oxygen saturation reflects the oxygen-carrying capacity of hemoglobin, theoretically the higher the better. After all, cells rely on oxygen for survival, so it is normal for blood oxygen saturation to be maintained between 95% and 100% when not breathing oxygen. When the saturation is maintained at 90%-95%, it should be taken seriously, and when it is lower than 90%, it is more dangerous.

Too low blood oxygen saturation means that human cells cannot obtain enough oxygen. The most typical manifestation is symptoms of hypoxia, such as fatigue, chest tightness, and shortness of breath.

When the lack of oxygen lasts for a long time, the body will experience cyanosis, and the skin and mucous membranes will turn blue due to lack of oxygen. If the lack of oxygen is not resolved for a long time, it will be life-threatening.

How to detect blood oxygen saturation?

The traditional detection method is to draw blood, use a blood collection needle to draw blood from the human artery, and use a blood gas analyzer to analyze the blood oxygen saturation in the blood. Its advantage is that the results are accurate, but its disadvantage is that it is an invasive test and can only be observed statically, not dynamically monitored.

With the advancement of technology, more and more finger-cuff blood oxygen saturation detection devices are now used in clinical practice. Friends who have undergone surgery must have a deep memory of the small instrument clamped on the finger. Its principle is very simple. Red blood cells combined with oxygen will absorb more infrared light, and it is the use of red light and near-infrared light technology to detect blood oxygen saturation. The most common is the non-invasive finger-cuff detector, and the same is true for Apple Watch.

Which diseases require regular testing of blood oxygen saturation?

1. Respiratory diseases

Blood oxygen saturation is a measure of hemoglobin's oxygen-carrying capacity. Patients with respiratory diseases are advised to have regular check-ups.

When the respiratory system is ill, the gas exchange of oxygen and carbon dioxide will be affected to a certain extent, especially for some patients with chronic respiratory diseases, because of poor lung function, the blood oxygen saturation is always low. When patients catch a cold or the original disease worsens, the blood oxygen saturation often decreases further, the patient's hypoxia symptoms worsen, and in severe cases, it may be life-threatening.

2. Sleep apnea syndrome

Sleep apnea syndrome is also known as sleep apnea hypopnea syndrome. The most typical manifestation is apnea during sleep. Especially for some obese patients, snoring is serious when sleeping, so serious that they hold their breath for a long time. At this time, the blood oxygen saturation will immediately drop, which will cause great damage to the organs of the whole body in the long run. For these people, it is recommended to monitor the blood oxygen saturation in time to avoid life-threatening due to low blood oxygen saturation.

3. Chronic cardiovascular disease

As the saying goes, "The heart and lungs are one family." Patients with poor heart function often have poor lung function. When oxygen cannot meet the body's needs, the heart can only pump blood faster to compensate, which increases the burden on the heart and induces heart disease. In severe cases, it can cause cardiac arrest.

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