Why is measuring heart rate from your finger so accurate?
Introduction: Why Finger Heart Rate Monitoring Now?
In recent years, smart rings have rapidly gained attention as health management devices.
One of the reasons for this is that measuring heart rate from the finger allows for high accuracy.
Until now, heart rate measurement has typically been done on the wrist, such as with smartwatches, but medical, research, and industrial applications require more stable data acquisition.
In this article, we will explain "Why the finger?" from three perspectives: sensor principle, human body structure, and wearing conditions.
Heart Rate Measurement Basics: What is a PPG Sensor?
How the PPG (Photoplethysmography) sensor works
Many smart rings and smartwatches use PPG (Photoplethysmography) sensors to measure heart rate.
The mechanism is very simple.
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Irradiating the skin with green or infrared LEDs
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Detects light reflection and absorption due to changes in blood volume
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Pulse rate is calculated from changes in blood flow synchronized with the heartbeat
In other words, the accuracy of the measurement depends on how stably the blood flow can be observed .
Why is the finger suitable for measuring heart rate?
Reason 1: The fingertips have a high concentration of blood vessels
The fingertips are one of the parts of the human body that has the most capillaries.
This structure evolved for thermoregulation and touch, resulting in strong and clear blood flow signals.
On the other hand, the wrist has many bones and tendons, and the position of blood vessels varies greatly from person to person, making the PPG signal prone to instability.
Reason 2: Simple bone structure and less noise
Fingers are structurally flat, which allows the sensor to easily come into close contact with the skin.
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Wrist: Complex structure of radius, ulna, tendons, and muscles
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Fingers: Short distance between bone and skin, simple structure
This difference allows for measurements on fingers that are less susceptible to motion noise and external disturbances.
Reason 3: High wearing stability (hard to slip off)
When measuring heart rate, even a slight misalignment of the sensor can be fatal.
Smartwatches are
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Too tight and uncomfortable
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If it is too loose, you are likely to have problems with missing data.
On the other hand, the smart ring
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Fixed to the shape of your finger
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Position does not change easily even during everyday activities
This allows stable heart rate data to be obtained continuously for 24 hours.
Finger measurement makes a difference in sleep and HRV measurements
Fingers are the best for measuring heart rate and HRV during sleep
Sleep analysis and **HRV (heart rate variability)**
It is necessary to capture the "subtle changes of each beat."
Measurements from the fingers are
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Strong blood flow signal
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Low body movement
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Little fluctuation due to pressure
For these reasons, it is very suitable for analyzing heart rate during sleep.
For this reason, smart rings are increasingly being used for high-precision sleep tracking in recent years.
Why smart rings are chosen for medical and industrial applications
Why a ring shape for research and corporate use?
In medical research and corporate health management,
Long-term, unconscious continuous measurement is more important than short-term accuracy.
The smart ring is
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Low wearing stress
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Does not interfere with life
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Less data loss
Due to these characteristics, it is being increasingly adopted in the B2B, medical, and occupational safety fields.
Summary: The future of heart rate monitoring lies in your fingers
Measuring your heart rate from your finger is more accurate because:
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High vascular density
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Simple bone structure
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The fit is stable
This is the optimal solution for the human body structure and physical conditions.
Smart rings aren't just new gadgets;
It is a next-generation wearable device that enables "more accurate and natural acquisition of health data."
In the future, in the fields of health management, medicine, and industry,
The question "Why fingers?" will become increasingly important.