Measuring blood pressure on Xiaomi Watch S1: reality or marketing?

Many users who buy the Xiaomi Watch S1 smartwatch expect to get a full-fledged medical gadget complete with a fitness tracker. The question of how to measure pressure on this device is one of the most frequent in search queries. However, faced with the lack of an explicit “Pressure” button on the menu, owners are confused. Is the watch really ignoring this feature, or does the user simply not know where to look for it?

The situation with measuring blood pressure (BP) in wearable electronics is more complicated than it seems at first glance. The optical sensors installed in the S1 are able to read the pulse and oxygen saturation of the blood, but to determine pressure requires either special inflatable cuffs or complex calibration algorithms that are not yet implemented in the global versions of the firmware MIUI Watch. In this article, we will discuss the technical limitations, ways of bypassing and the real capabilities of the device.

It is important to be clear: the Xiaomi Watch S1 as standard and stock firmware do not have a built-in direct blood pressure measurement function. Attempting to find a hidden menu or activate this option through engineering codes will likely come to nothing and can disrupt the software.

Technical limitations of optical sensors

The sensors in the Xiaomi Watch S1 are based on PPG technology, which is used to show skin through LEDs, and the sensor analyzes changes in blood flow, which allows you to accurately determine heart rate (HR) and heart rate variability (HRV), but blood flow velocity alone is not enough to calculate systolic and diastolic pressure.

There are methods for assessing pulse wave pressure (PTT), but they require individual calibration for each user using a classic tonometer. In the current version of the software, the calibration algorithms for this model are not activated by the manufacturer, and this is done to avoid providing users with inaccurate medical information that could lead to serious health consequences.

⚠️ Warning: Don't rely on smartwatch readings to make drug decisions. Optical methods without calibration can reach critical values.

Xiaomi developers rely on data security, so the functionality is limited to those parameters that can be measured with guaranteed accuracy. If you need constant monitoring of blood pressure, it is worth considering specialized medical bracelets with an inflatable cuff, which, however, lose the S1 in autonomy and screen quality.

Monitoring the pulse as an indicator of the state

While direct pressure measurement is not available, the Xiaomi Watch S1 does a great job of tracking heart rate, which is an important indirect sign.Sharp surges in heart rate at rest can signal increased pressure or stress.To activate continuous monitoring, you need to go to your health settings through the Mi Fitness app.

You can adjust the frequency of measurements in the app, and the following intervals are available:

• 🟢 Measurement every minute (maximum accuracy, high battery consumption)
• 🟡 Measurement every 10 minutes (optimal balance)
• 🔴 Measurement every 30 minutes (economical mode)
• ⚫ Only during training.

Using continuous monitoring, you can plot a detailed heart schedule every day, and you can see patterns like a heart rate rise in the morning or after a certain meal, and that's valuable information for a cardiologist to make a diagnosis.

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For maximum accuracy, hold your watch tightly against your wrist, but do not press your veins. It is better to hold your hand at heart level while measuring.

It's worth noting that the accuracy of the readings depends on the density of the strap. If you plan to use pulse data to analyze the state of the vessels, make sure that the sensor on the back is clean and not covered with clothes or hair.

Synchronization with external tonometers

Because there is no native blood pressure measurement feature, the only way to get a complete picture of health is to integrate data from external sources.The Mi Fitness ecosystem allows you to synchronize data with Xiaomi and iHealth smart blood pressure monitors. This creates a single database of your health.

The process of data consolidation is as follows:

1. Connect the smart tonometer to the Mi Fitness or Xiaomi Wear app.
2. Make pressure measurements on the tonometer according to the instructions.
3. The data will be automatically transferred to the cloud and displayed in the general Health tab.
4. This data will not be displayed on the watch, but will be available for analysis in the smartphone.

This approach allows you to correlate your heart rate with the Xiaomi Watch S1 and your blood pressure data, so for example, you can see how your heart rate changes immediately after a pressure surge, and this gives you a more complete picture of your body's response.

Use of the clock bundle + The tonometer is the most professional approach to self-control, and you get the benefits of a stylish wearable sports device and notifications without losing the accuracy of medical indicators.

Third-party applications and risks of modification

There are also some online references to third-party WearOS apps or modified versions of Mi Fitness that allegedly activate pressure measurements. APK-files directly to the watch. Technically, Xiaomi Watch S1 base-work RTOS, Not full-fledged WearOS, which limits the installation of arbitrary software.

Attempts to install unofficial software carry serious risks:

• 🚫 Possible loss of warranty on the device.
• 🚫 High risk of clock bricking when installing incompatible firmware.
• 🚫 Incorrect operation of sensors and fast battery discharge.
• 🚫 Leakage of personal health data.

⚠️ Warning: Installing untested software from unknown sources can cause permanent damage to the watch software.

Some enthusiasts try to use pulse and age-based pressure algorithms through third-party services, but these calculations are highly inaccurate and cannot even be considered an approximate measurement.

Set up high pulse notifications

To compensate for the lack of pressure monitoring, it is recommended to make the most of the high pulse notification feature.The Xiaomi Watch S1 can vibrate if your resting heart rate exceeds a set threshold.This can be an early signal of pressure or stress problems.

To set up, perform the following actions:

1. Open the Mi Fitness app on your smartphone.
2. Go to the device profile and select “Health settings”.
3. Find the item “Hard rate monitoring” or “Warnings”.
4. Set a threshold (e.g., 100 or 110 beats per minute).
5. Activate the “Warn about high pulse” switch.

This feature is especially useful for people who are active or at risk, and the watch will quietly remind you to rest or measure your blood pressure manually if your heart rhythm goes beyond normal.

Factors affecting the accuracy of measurements

Even when measuring the pulse, which is the basis for all health calculations, it is important to consider external factors: tattoos, thick wrist hair or too loose a strap can distort the optical sensor readings.

Ambient temperature also plays a role, and in cold weather, vasoconstriction can make it difficult to read the signal, and in winter, it is recommended to warm your wrist a little before measuring, and moving your hand during measurement can interfere with the algorithms.

To obtain the most reliable data on the state of the cardiovascular system:

• 🧘 Take measurements in a calm state, sitting or standing.
• 👐 Hold your hand with your clock motionless at chest level.
• 🧼 Regularly wipe the back of the watch from sweat and pollution.
• 🔋 Watch the battery level (at low charge, accuracy may fall).

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The accuracy of biometrics depends on the correctness of the device and the state of the sensor, and regular cleaning and tight fitting of the strap is the key to the correct reading.

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