SpO2 on Xiaomi Watches: What is it, How Does It Work, and Why You Should Measure It?

Have you ever noticed on the screen of your smart watch Xiaomi mysterious acronym SpO₂ And they wondered, what does it mean? It's an integral part of today's fitness trackers, but not everyone understands what it means and what it means. 6/7/8, Xiaomi Watch S1/S2 or another model with an oxygen sensor in the blood - this article will help to understand all the nuances.

SpO₂ (Oxygen saturation is the percentage of oxyhemoglobin in your blood that shows how efficiently your body is saturated with oxygen. With pandemics, growing interest in healthy lifestyles, and the spread of pulse oximeters, this has become a key indicator for monitoring well-being, but how exactly does Xiaomi measure it through a wristwatch, how accurate is this data, and when should it sound the alarm? Let's get this straight.

What is it? SpO₂ And why is it important?

abbreviation SpO₂ It stands for Saturation of Peripheral Oxygen, which is oxygenation in peripheral blood, and in medical practice, it's measured using pulse oximeters, devices that are attached to your finger, earlobe, or wrist. The normal saturation values for a healthy person are 95-100%, a fall below 90% is already considered hypoxemia (oxygen starvation) and requires medical intervention.

Why is this indicator important?

• 🩺 Diagnosis of respiratory diseases: low SpO₂ may indicate pneumonia, COPD, or even an asymptomatic course COVID-19.
• 🏃 Sports loads: monitoring saturation helps to assess the effectiveness of training and avoid overload.
• 😴 Sleep quality: Nocturnal apnea (respiratory arrests) are often accompanied by a drop in oxygen levels.
• ⛰️ Altitude adaptation: Saturation naturally decreases in the mountains and control helps to avoid altitude sickness.

Xiaomi’s smartwatches don’t replace the medical pulse oximeter, but they do allow you to track the dynamics of the indicator in everyday life, the main thing is to understand the limitations of the technology and not rely on it in critical situations.

How Xiaomi Watches Measure SpO₂: technology

The saturation measurements on Xiaomi watches are based on photoplethysmography (PPG) technology. The sensor emits two-length light waves (usually red and infrared) that penetrate the skin and reflect off blood vessels. Oxygen-rich hemoglobin and oxygen-free hemoglobin absorb light differently. By analyzing the reflected signal, the watch calculates the percentage of saturation.

The accuracy of such measurements depends on several factors:

• 📊 Sensor quality: in Mi Band models 7/8 Xiaomi Watch S2 It uses better sensors than older versions.
• 💡 Lighting: bright sunlight or lack of lighting can distort results.
• 🖐️ Hand position: the sensor should fit tightly to the wrist, but not to press the vessels.
• 🩲 Skin temperature: Cold fingers or poor circulation reduce accuracy.

According to the study, the error of measurements SpO₂ On wearable devices, it can reach ±2-4 percent compared to medical devices, which means that if your watch is 92%, the real value could be between 88% and 96.

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Before the measurement SpO₂ Warm your hands, remove the nail polish (if the sensor is located on your finger) and keep your hand still for 10-15 seconds.

What Xiaomi Watch Models Support Measurement SpO₂

The oxygen saturation monitoring feature has been introduced to Xiaomi’s ecosystem relatively recently. Below is a table of models that support measurement. SpO₂, and their peculiarities:

Note that even in models that support automatic measurement (such as Mi Band 8), the default function can be disabled to save battery power. → Health monitoring → SpO₂ and set up a schedule.

How to measure correctly SpO₂ Xiaomi watches: step-by-step instructions

The process of measuring saturation on Xiaomi watches is simple, but requires a few rules to obtain reliable data.

1. Preparation: Sit in a comfortable position, relax your hand. Make sure that the sensor on the back of the watch fits tightly to the skin, but does not squeeze the wrist.
2. Activation: On Mi Band: swipe up on the home screen → choose "SpO₂". On Xiaomi Watch: Find the Oxygen app in the menu or add it to the home screen.

Measurement

The result

If the result seems unusual (e.g., 85% for well-being), repeat the measurement in 5-10 minutes. SpO₂ Below 90% without other symptoms does not always indicate a problem - it can be an artifact of movement or poor sensor contact.

What to do if SpO₂ Xiaomi watches show low values

If your watch regularly gets saturation below 92-93%, don't panic, but don't ignore the signal.

⚠️ Note: If you are with a low SpO₂ You have shortness of breath, dizziness, blue lips or fingertips — seek medical attention immediately, and these may be symptoms of serious breathing or cardiovascular problems.

Steps to improve saturation:

• 🌬️ Breathing exercises: deep, slow breaths through the nose and exhalations through the mouth (e.g. technique) 4-7-8: breath 4 bills, delay 7, breath out 8).
• 🚶 Light physical activity: a short walk in the fresh air improves lung ventilation.
• 💧 Hydration: dry air irritates the airways. Use a humidifier or place a container of water next to the battery.
• 🛌 Change in body position: if low SpO₂ fixed at night, try sleeping on your side or with your head raised.

If after these measures, the indicator does not normalize within 1-2 days, make an appointment with a therapist or pulmonologist. Take with you data from the Mi Fitness application - change schedules. SpO₂ In a week, the doctor will help to assess the dynamics.

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Low. SpO₂ At night, if there are no symptoms during the day, it may indicate obstructive sleep apnea syndrome, a condition in which breathing periodically stops during sleep.

Comparison SpO₂ Xiaomi watches with medical pulse oximeters

Many users question the accuracy of the smartwatch and compare it to medical pulse oximeters, so let's see if these doubts are justified.

In 2022, the Journal of Medical Internet Research published a study comparing the accuracy of 10 popular fitness trackers (including Mi Band 6) with certified pulse oximeters.

• 📉 The average error of Xiaomi was ±3.2% (for comparison, the Apple Watch — ±2.8% at Garmin — ±2,5%).
• 🔍 Accuracy dropped when the hand moved or the sensor was weak.
• 🌡️ In the range of 90-100%, the results were closer to real than at values below 85%.

This means that Xiaomi watches are suitable for tracking trends (for example, how saturation changes after workout or in sleep), but not for making diagnoses. If you want an accurate value, use a medical pulse oximeter (for example, Xiaomi Mi Oxygen Monitor, which is attached to your finger).

Frequent errors in measurement SpO₂ and how to avoid them

Many users are faced with incorrect indicators SpO₂ Xiaomi watches because of common mistakes, and here are the most common ones and how to fix them:

If problems persist even after the obvious causes are eliminated, try resetting the clock to factory settings. Go to Settings → System → Reset. Remember that after resetting, all local data (except those synchronized with the application) will be deleted.

FAQ: Answers to frequent questions about SpO₂ Xiaomi watch