Can Fitbit And Apple Watch Do What Dhyana Does?

By Author: anjali
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Dhyana began as a scientific project to capture heart rate variability. The link between heart rate variability (HRV) and the Autonomous Nervous System (ANS) has been well established, with the scientific community agreeing that high frequency variations in heart rate variability correlated to less stress.

We were tasked by a German multinational to look into HRV in those who meditated. While there was a lot of research already conducted, they had requested us for more data for an analytical study on the affects of meditation.

While working on this project we began by looking tools for acquiring this data. To do so, we visited the Hong Kong Trade Development Conference in 2017 and were offered many smart watches, which could calculate heart rate. Apart from hundreds of Chinese watches we also had the Apple Watch, FitBit, Garmin, Goquii, MiBand, Honor Band and so on.

These devices also started to give us heart rate data; but as we collected this data we soon realised was that wrist borne heart rate monitors are incapable of getting HRV.

To understand why, we need to understand how these heart rate ...
... monitor watch manufacturers calculate heart rate.

Most of us would notice that heart rate monitors on the wrist emit green light into your wrist. This green light senses your blood flow, and hence understands when your heart beats. This form of measurement is called Pulse Plethysmography (PPG).

This form of measurement was introduced for parts of the body which had thin skin like the finger or your ear lobe. Pulse Oximeters like those you’d have seen in a hospital use them. But watch manufacturers modified them for the wrist. Unlike the finger and the earlobe, wrists have a much thicker layer of skin, and contain more biological parts, such as a joint, ligaments, muscles, tendons to name a few.

So when this technology was used to capture heart beat information from a simple cartilage like your ear or from some skin and bone like your finger, the method of getting the same information from the wrist was akin to finding a needle in a haystack. However, modern technology did permit them the ability to do that with a certain degree of accuracy, which has been debated widely.

To hide their lack of accuracy, these watch manufacturers then average the heart rate information vigorously. This is why you rarely see your heart rate change multiple times a minute.

Let’s take your current heart rate monitor, like the Apple Watch or the FitBit, and see your current heart rate. It may (for example) show a value like 78 BPM. In HRV terms, that means you will have 78 different data points in a minute in HRV, however these watches strangely only display one value – 78. So is 78 real? Did it actually record 78 different beats and count them up to display that value?

These watches in a period of a minute acquire maybe 2-3 data points, and not 78. From these 2-3 they make (for lack of a better term) a guesstimate on what your Heart Rate is. This problem makes heart rate from these devices unreliable as reported all over the world.

While watches like the Fitbit and Apple Watch may be great for showing heart rate, they are not as good for calculating heart rate variability. This medium article elaborates on it more.

This is the reason why Dhyana is different. dhyana gets all 78 data points, which is critical for understanding your state-of-mind. So when we say dhyana is the most accurate HRV monitor we say it with pride, because we have tried everything else out there that’s commercially available.

What makes Dhyana unique? Well the plain and simple truth is, Dhyana is not worn on the wrist. It’s a ring, which slips on to your finger. It’s not rocket science, when we realised that everywhere we had inaccurate heart rate monitors, we took a step back, and with a cool head understood that accuracy doesn’t lie in creating new technology, but revisiting old ones.

If it ain’t broke, don’t fix it

To find out why Heart Rate Variability is so important to understanding your state-of-mind please read the following article.