What is Pulse Wave Velocity?
Each time your heart beats it induces a wave along the aorta and arterial tree.
This wave leads to blood volume changes in the vessels that expand and contract in response to these changes.
Pulse Wave Velocity is the propagation speed of this wave along the arteries. Increased stiffness of the arteries increases Pulse Wave Velocity. It allows you to evaluate your cardiovascular health.
What does the Pulse Wave Velocity say about me?
Used by the medical community as well, it is the synthesis of our lifestyle and of the main cardiovascular risks: the state of our arteries and blood pressure variations.
“Decreasing PWV shows cardiovascular state improvement.” Professor Pierre Boutouyrie, European Society of Hypertension
“Elevated PWV is jointly associated with future systolic blood pressure and incident hypertention.” Dr. Gary Mitchell, Framingham Heat Study
Diseases such as diabetes, cholesterol or high blood pressure induce stiff arteries, which lead to an elevated Pulse Wave Velocity.
An elevated Pulse Wave Velocity is a sign of poor heart health, indicating a risk of having or developing high blood pressure. On the other hand, the more flexible the artery, the better your heart health.
What are the pathologic risks associated with high Pulse Wave Velocity?
Medical research has demonstrated a strong correlation between the stiffness of the arteries and the risk of a cardiovascular incident. Stiffer arteries indicate a greater risk for high blood pressure, stroke or heart attack.
Pulse Wave Velocity has been proven to be as reliable as the Framingham risk score, which is currently the most common way of predicting one’s risk of cardiovascular incident. Unlike the Framingham risk score, Pulse Wave Velocity is a direct measurement of your cardiovascular health.
Can I improve my Pulse Wave Velocity?
The good news is that you can decrease your Pulse Wave Velocity with healthy lifestyle changes. If you are overweight or obese, losing weight can have a tremendous impact. Engaging in physical exercise, and limiting salt and alcohol intake may also help to decrease your Pulse Wave Velocity. Additionally, managing stress can help you avoid elevated heart rate and blood pressure readings that can hurt your arteries over the long term.
Paired with the Body Cardio, the Health Mate app interprets measurements and trends based on age, and tailors recommendations to improve cardiovascular health accordingly.
How does the Body Cardio measure Pulse Wave Velocity?
The Body Cardio computes Pulse Wave Velocity based on a person’s age and the time it takes for blood to go from the aorta to the vessels in the feet.
Thanks to its sensors, the Body Cardio detects slight weight variations on the scale caused by heartbeats. With this information, the scale can sense the moment when blood is ejected from the aorta and the moment when it reaches blood vessels in the feet. The time between these two events is then compared to the user’s height, and the Body Cardio can compute the Pulse Wave Velocity in approximately 15 seconds.
Note that after installing your Body Cardio, you will need five valid measurements before you can access the Pulse Wave Velocity graph. These measurements are required to calibrate Pulse Wave Velocity measurement on your scale. You will receive a Timeline item every time you get a valid measurement, and a final one once you can access the graph.
Why do my Pulse Wave Velocity measurements vary throughout the day?
Various factors can lead to variations in blood pressure and Pulse Wave Velocity:
- coffee consumption
- stress level
- physical activity level
- time of day
- alcohol intake
The best way to assess your cardiovascular health is to measure your Pulse Wave Velocity over time.
Getting a reliable measurement
Follow these tips to improve the reliability of your measurement:
- Measure your Pulse Wave Velocity in a quiet room with stable temperature (ideally 71.6-73.4°F / 22-23°C).
- Measure your Pulse Wave Velocity at the same hour every day, and at least three hours after a meal, drinking coffee or smoking a cigarette.
- Try to take the measurement without moving or speaking.
How was this measurement developed on the Body Cardio?
To assess the validity of the measurement of the Body Cardio, Withings has performed a study following the recommended guidelines, which compared the measurement of the Aortic Pulse Wave Velocity by the Body Cardio to a Sphygmometer, which is reserved for the medical field.
The preliminary study was conducted on a group of more than 100 individuals in a clinical setting by a medical team specializing in arterial stiffness (Professor Pierre Boutouyrie, European Hospital Georges Pompidou, Paris, France). The results of this study demonstrates that Pulse Wave Velocity measurements taken with the Body Cardio yielded similar results to measurements taken using the Sphygmometer. These results will be published at the European Society of Hypertension Congress in Paris in June 2016. Furthermore, a multicentric study is underway to confirm these results.
How is Pulse Wave Velocity currently used in medical procedures?
Despite its obvious medical value, Pulse Wave Velocity has been restricted to those already diagnosed with high blood pressure to assess damage that may have occurred because of their condition.
Indeed, the traditional measurement takes at least 20 minutes, uses a specific device called a sphygmometer, and requires a well-trained operator to perform the measurement.
Because of its complexity, Pulse Wave Velocity measurement is not widespread, even in a hospital setting. But now, for the first time, Pulse Wave Velocity can be measured at home via the Body Cardio to assess overall cardiovascular health.
Will the use of blood pressure medication affect the results of Pulse Wave Velocity reading?
Randomized controlled trials following patients initiating an antihypertensive treatment show that PWV is reduced during treatment. The magnitude of the reduction, and whether the reduction of PWV goes beyond what is simply expected from the reduction of blood pressure and/or heart rate, depends on the drug or drug association.
What is the difference between Pulse Wave Velocity and Vascular Age?
Pulse Wave Velocity (PWV) and Vascular Age (VA) are two indexes of your cardiovascular health. They are related, but their interpretation is slightly different because the "optimal," "normal," and "not optimal" ranges are defined differently for each.
Withings introduced PWV in 2016 after calibrating and validating Body Cardio against the gold standard for PWV measurement. This gave us the possibility to refer to the PWV normality ranges published in scientific literature. These "normal values" were established on large groups, totaling over ten thousand patients in a clinical context over decades.
With VA, we extend this work on PWV by leveraging the fact that since 2016 we have the largest, most up-to-date database of PWV measurements in the world, with over one hundred thousand measurements. VA offers an interpretation of the PWV results based on measurements of other Body Cardio users.
As a whole, users of Body Cardio have slightly different demographic and clinical characteristics than the populations of patients on which the normal ranges of PWV were established. As a result, the "optimal," "normal," and "not optimal" ranges of PWV and VA do not coincide exactly with one another. As such, if your PWV is close to the border of a range (for instance close to the border between "normal" and "not optimal"), your VA may fall into the neighboring range (in this example, "not optimal").