Xiaomi Mi Band 5 is one of the most popular fitness trackers, which can not only count steps and monitor sleep, but also measure the level of oxygen in the blood (SpO₂). This feature, known as saturation, helps to assess blood oxygen saturation and detect possible problems with breathing or cardiovascular system. how exactly this option works, how accurate the readings are, and how to correctly conduct measurements so that the results are as reliable as possible?
In this article, we will learn how to measure the saturation on the Mi Band 5, what settings to activate, how to interpret the data obtained and what to do if the readings seem inaccurate, and you will learn about the hidden nuances of sensor calibration, which Xiaomi does not mention in the official instructions, but which directly affect the accuracy of the measurements.
What is saturation and why it is measured with a fitness bracelet
Saturation (SpO₂) — This is the percentage of oxygen in the blood relative to the maximum capacity, which is normally 95-100% in a healthy person, and a decrease below 90% can indicate hypoxia (oxygen starvation), which requires medical intervention. Fitness bracelets, including the Mi Band 5, measure saturation using an optical sensor that analyzes light absorption by hemoglobin.
Why is this necessary in everyday life?
- 🏃♂️ Sports loads: Controlling saturation helps avoid overstrain, especially when running at high altitudes or intense training.
- 😴 Sleep monitoring: A drop in oxygen levels at night may signal apnea (stopping breathing).
- 🌡️ General well-being: a sharp decline SpO₂ Sometimes it is the first sign of a cold, COVID-19 or other respiratory diseases.
- ⚠️ Prevention: Regular measurements are useful for people with chronic lung or heart disease.
It's important to understand that the Mi Band 5 is not a medical device, and its readings are indicative, and it always requires professional equipment to diagnose, but the tracker can be a useful tool for self-monitoring and timely medical attention.
⚠️ If your saturation consistently shows values below 92% for no apparent reason (for example, after an intense exercise), consult your doctor immediately.
Mi Band 5 Preparation for SATURATION Measurement
Before you start measuring, you need to make sure that the bracelet is properly set up and ready to work.
Update the bracelet firmware to the latest version
Install or update the Mi Fit (or Zepp Life) app
Activate the function of measuring saturation in the bracelet settings
Charge the bracelet to at least 20% (optimally 50% and above)
Put the bracelet on your hand so that the sensor is tightly attached to the skin.-->
Pay special attention to the density of the sensor, if the bracelet is too loose or moved to the side, the reading will be inaccurate, the optimal position is 1-2 cm above the wrist bone, without clamping blood vessels.
Also check if the measurement function is enabled. SpO₂ appendix:
- Open Mi Fit or Zepp Life.
- Go to the Profile section → Mi Smart Band 5 → Settings of the device.
- Find the Measurement item SpO₂ and activate it.
- If necessary, set up an automatic measurement during sleep (recommended for monitoring sleep apnea).
Once a day.
Several times a week
Only when you're feeling bad.
I never used this function.-->
Step-by-step: how to measure saturation on Mi Band 5
Measuring process SpO₂ Mi Band 5 takes about 30 to 60 seconds. Here's how to do it right:
- Put the bracelet on your hand (preferably on your left, as your right might be disturbed by your watch or other accessories) Make sure the strap is not too tight, but it doesn't hang around either.
- Activate Measurement Mode: Swipe down the bracelet screen to open the menu. SpO₂ (You can see the lungs or the wave graph. You can click on it and confirm the beginning of the measurement.
Keep still.
Wait for the process to end.
Watch the story.
Mi Fit
Zepp Life
Health → SpO₂
If the bracelet does not find a function SpO₂, check:
- 🔄 Is the firmware updated (in Mi Fit go to Device Profile) → Update of the PO).
- 📱 Is the app version compatible with your bracelet model (Mi Band 5 requires Mi Fit version 4.6.0 and higher).
- 🔋 Is the battery enough (at a level below 10%, some functions are turned off).
What if the bracelet does not measure saturation?
How to interpret results: norm and deviations
Once you get the saturation reading, it's important to get it right.
| Level. SpO₂ (%) | Interpretation | Recommendations |
|---|---|---|
| 95–100% | Normal blood oxygen levels. | Continue monitoring as normal. |
| 91–94% | A slight decrease in saturation, can be observed during exercise or at altitude. | Repeat the measurement in 10-15 minutes. If the value has not recovered, pay attention to your health. |
| 86–90% | Moderate hypoxia. It requires observation. | Eliminate external factors (smoking, stuffy room) If repeated low values, consult a doctor. |
| 85% and below | Severe hypoxia, dangerous to health. | Seek medical attention immediately. |
It is important to consider the context in which the measurement was carried out:
- 🏔️ At an altitude of more than 2,500 meters above sea level, saturation can naturally decrease to 90-92%.
- 💨 After intense training, a temporary drop to 93–95% is normal if it recovers within 5–10 minutes.
- 😷 For colds or COVID-19 low-down SpO₂ (For example, up to 94% of the time may be a warning sign.
⚠️ Note: If you smoke or are in a smoky room, saturation readings may be overstated due to the effect of carbon monoxide (CO) In this case, the actual oxygen level in the blood may be lower than the bracelet indicates.
Measurement accuracy: how much can you trust the Mi Band 5
The accuracy of pulse oximetry on fitness bracelets is one of the most controversial issues, unlike medical pulse oximeters, which are certified and have a margin of error of no more than one. ±2%, Mi Band 5 can give deviations up to ±This means that if the bracelet is 95 percent, the real value could be in the 90-100 range%.
Accuracy is influenced by several factors:
- 🩸 Skin color and tattoos: Dark skin or wrist tattoos can absorb sensor light, distorting results.
- 💡 Lighting: bright sunlight or artificial lighting (especially lighting) LED) thwart.
- 🧊 Ambient temperature: at low temperatures, blood circulation in the extremities deteriorates, which can underestimate the readings.
- 🔋 Battery charge: At a charge level below 15%, the sensor may not work smoothly.
To improve accuracy, follow these tips:
💡
Before you measure saturation, warm your hands by rubbing them against each other or holding them under warm water, which will improve circulation and reduce error.
It is also useful to compare the Mi Band 5 readings with a medical pulse oximeter (if possible), for example, in user tests the difference between the bracelet and the certified device averaged 1-3%, but in some cases reached 7%.
Automatic monitoring of sleep saturation
One of the most useful features of the Mi Band 5 is night monitoring. SpO₂. It helps to identify episodes of sleep apnea that often go unnoticed but are seriously harmful to health:
- Open the Mi Fit or Zepp Life app.
- Go to Profile. → Mi Smart Band 5 → Sleep monitoring.
- Enable the Measurement option SpO₂ dreamily.
- Adjust the frequency of measurements (recommended 1 time in 30 minutes for a balance between accuracy and battery consumption).
When you wake up, you can see the schedule of changes in saturation over the night.
- 📉 Sharp drops below 90% are a possible sign of apnea.
- 🕒 Duration of low saturation episodes (more than 10 minutes).
- 🔄 Frequency of vibration: If the chart is similar to a roller coaster, it may indicate unstable breathing.
Example of the graph with problem areas:
SpO₂ (%)
100 | ●
| / \
95 | / \
| / \
90 | ●───────● ●───────●
| / \ /
85 | ● \ /
+----------------------------→ Time.
22:00 02:00 06:00This graph shows two critical saturation drops (about 02:00 and 05:30) that may be associated with apnea. If such episodes recur regularly, you should consult a sleep therapist.
💡
Automatic monitoring SpO₂ Sleep is one of the most effective ways to diagnose apnea early, but it requires polysomnography in the clinic to confirm the diagnosis.
Frequent Mistakes and How to Avoid Them
Many users make errors in measuring saturation, leading to inaccurate or inconsistent results, and the most common are:
- Measurement in motion. Even a slight tremor of the hand distorts the data. Always take it at rest.
- If there's a gap between the sensor and the skin, the lights will scatter and the readings will be incorrect.
- Measurement immediately after exercise, blood flow in the hands is increased, which can overstate or underestimate the results. Wait 5-10 minutes.
- Using a bracelet on your right hand (if you are right-handed) may cause blood circulation on your leading hand to be different due to the load.
- Neglect of calibration: After buying or resetting the bracelet may require initial sensor settings.
To minimize errors, follow this algorithm:
Sit down or lie down, relax your hand.
Wear the bracelet tightly, but without clamping.
Make sure the sensor touches the skin (no hair, dirt)
Do not talk or move during the measurement.
Repeat the measurement 2-3 times at intervals of 1 minute-->
If the results are consistently different from the expected, try resetting the sensor settings:
- In the Mi Fit app, go to the Device Profile → Additional settings.
- Find the item Reset sensors (or Calibration).
- Confirm the reset and repeat the measurement in 10 minutes.