Filter
Top Products
2196-5
Velocity
Blood pressure value
Fast pulse wave velocity
High blood pressure
Slow pulse wave velocity
Low blood pressure
High blood
pressure
Low blood
pressure
Slow
= Takes
longer
Fast
= Takes
less time
Operating principle of
standard blood pressure
measurement
Operating principle of
this Watch
Pulse wave
transit time
measurement
Substituted in formula
for estimating blood
pressure
Blood
pressure
value
Blood
pressure
value
Inflation of
cuff on upper
arm
Detection of
pressure by sensor
Pulse Wave Velocity
The change in blood vessel volume over time caused when the heart
contracts is called a “pulse wave” (or “volume wave”). The time it takes
for the pulse wave to reach a particular part of the body is the “pulse
wave transit time (PWTT),” and the speed that the pulse travels is called
the “pulse wave velocity.”
This watch measures the pulse wave transit time at the tip of a finger
placed on a sensor, and uses this information to estimate blood pressure.
Pulse Wave Transit Time (PWTT) measurement
Though the procedures in this manual refer to a single sensor on the
front of the Watch, there are actually three sensors that provide the data
required to calculate blood pressure as described below.
The Watch’s electro-potential sensor (the Watch’s sensor where you
place your finger is the negative terminal while the back of the watch in
contact with your wrist is the positive terminal) detects the electrical
signals generated right about the time the heart contracts. This electrical
signal is the starting point of the pulse wave transit time. The Watch
calculates the time between the electrical signal generated by the
heartbeat and detection of the pulse wave at the fingertip placed on the
Watch’s sensor to determine the pulse wave transit time.
Photosensor*1
Electro-potential
sensor
–
*2
Side
Electro-
potential
sensor
+
*3
Electro-
potential
Pulse
Wave
Pulse Wave Transit Time
Time
*1 This sensor detects when a pulse wave reaches your fingertip.
*2 This sensor is the negative (
–
) electrode used for detecting
differences in the body’s electro-potential.
*3 The entire back of the Watch acts as a positive (
+
) electrode, which
is used for detecting differences in the body’s electro-potential.
Why is basic data necessary?
Though pulse wave velocity and blood pressure are roughly proportional,
there tend to be slight differences from person to person. Because of
this, the relationship between the measured blood pressure value and
the pulse wave velocity of the particular individual for whom blood
pressure readings are to be taken must be measured (using the Base
Unit) and sent to the Watch so it knows what allowances need to be
made for that individual. This relationship, which is different for each
person, is called “basic data.” The Watch must have correct basic data
(measured pulse wave velocity data) in order to calculate proportional
blood pressure values.
Pulse wave
transit time
(detected)
Blood
pressure
(input)
Determine
relationship
Setting basic data
Pulse wave
transit time
(detected)
Blood
pressure
(calculated)
Calculate
blood
pressure
Reading by Watch
Note
• It is important to remember that correct blood pressure measurements
are impossible unless you correctly set your basic data.
• The message on the display of the Watch indicates that
there is no basic data in the Watch’s memory. You cannot use the
Watch to take blood pressure readings while this message is on the
display.
• The Base Unit is required in order to set basic data.
When to use the Watch
This Watch calculates blood pressure values based on pulse wave
transit time, so there is no need to apply pressure to the upper arm. This
means that blood pressure readings can be taken quickly and easily,
without the need for complex equipment or procedures. The compact
watch-type configuration means you can take it along just about
anywhere.
It should be noted that the Watch does not actually measure blood
pressure, but rather it calculates an estimated blood pressure value.
Because of this, there is some element of error in the readings produced
by the Watch. The chance of error is increased by your personal
physical properties and by the environment where you are taking a
reading.
Be sure to use the Base Unit whenever you need accurate measurement
of your blood pressure. Use the Watch when you are out and need to
have a general idea of your current blood pressure.
When is the best time to set basic data?
Set basic data in a quiet place, while you
are physically and emotionally relaxed.
Example: Before breakfast, after rising
Important!
Individuals on blood pressure reduction
medication may experience large errors in
blood pressure readings. Consult your
physician if you have any doubts about the
readings produced by this Watch.
Tips on Placing Your Finger on the Sensor
The Watch uses the data detected through its sensors to calculate blood
pressure. If it cannot pick up data through the sensors, an error message
appears on the display. Note the following points if you experience
problems with measurements.
• For details about error messages, see “Error Messages When Setting
Basic Data”, and “Blood Pressure Reading Error Messages”.
Be sure to wear the Watch on your left wrist.
The back of the Watch is designed to act as a sensor, and it must be in
close contact with your left wrist.
Finger Placement
Place your finger on the sensors (photo
sensor and electro-potential sensor) as
shown in the illustration.
No matter how you place your finger on the
sensors, you should use the same finger for
blood pressure and pulse measurements
that you used when setting your basic data.
Otherwise, measured data may be wrong.
Left wrist
Electro-potential
sensor
+
Electro-potential
sensor
–