How does Dhyana measures HRV image

How does Dhyana measures HRV

Article by: Bhairav Shankar

Measuring the rate of a patient’s heart beat is a pretty simple procedure and requires almost no tools or electronic whatsoever. One can measure it as simply as placing one’s ear against a patient’s chest while staring at a clock. Apart from the misfortune of being caught in this compromising position, the place-ear-against-chest method does suffer from a few further issues. The count can be interrupted with something as small as a cough, and measuring one’s heart rate for long durations of time, would require placing one’s ear affixed against a patient’s chest for said lengthy durations, an unpleasant feeling at the very least. To save their children’s chest from having a head attached to it, scientists across the world came up with new and innovative methods to measure heart rate.

But why is measuring heart so important?

The heart has played an important role in understanding the body since antiquity. In the fourth century B. C., the Greek philosopher Aristotle identified the heart as the most important organ of the body, the first to form according to his observations of chick embryos. It was the seat of intelligence, motion, and sensation – a hot, dry organ. Aristotle described it as a three-chambered organ that was the center of vitality in the body. Other organs surrounding it (e.g. brain and lungs) simply existed to cool the heart.

Science has advanced a bit from the time of Aristotle. For one thing, the heart has now been retconned to be as a muscle which thermoregulates the body and provides nourishment to all parts of the body by being the central engine that runs the circulatory machine. The heart is the most used indicator for proof of life, and its poor health is now the leading cause of death across the world.

Figuratively the heart now can be cold too, much like the one that a doctor could accuse their wife of having when their wife didn’t save any dinner for the doctor who’s spent the whole day saving lives, albeit by placing their ear to patients’ chests due to a faulty stethoscope.

However before one delves into how heart rate is measured automatically with the use of devices, it’s important to understand how the heart beats and what the biological consequences of such beating are.

The sinoatrial node (SAN) in the heart regulates the heart’s pumping, by sending a small electric impulse that commands the muscles in the heart to either relax or tense. The SAN is controlled by the Autonomic Nervous System (ANS), and hence the beating of heart changes depending on the state of one’s ANS. For example, a relaxed ANS would be considered to be parasympathetic and it commands the heart to beat at seemingly regular and slow intervals, however when the ANS is stressed it would be called sympathetic and is characterised by a heart that is beating much faster and is who’s consecutive beats arrive at more unpredictable intervals.

The ANS commands the heart to pump the blood via the SAN, the heart pumps oxygen and nutrition filled blood to all parts of the body. And when the SAN commands the heart to relax, the blood returns back to the heart after depositing all its nutrition and collecting any waste.

Scientists measure the heart at various points via multiple methods: electrocardiography, ballistocardiography, photoplethysmography, echocardiography and so on. The two predominant ones used by engineers are scientists across the world to measure heart rate are electrocradiography (EKG) and photoplethysmography (PPG).

EKG measures the electrical signatures around the torso, and in specific the functioning of the SAN. Heart rate from an EKG counts the number of times the SAN is activated in a minute.

PPG measures the pressure of the blood via optical sensors and checks how often nutritious blood reaches a peripheral in the body every minute.

The main advantage that permits PPG to be used in most wearable devices is because PPG requires only one sensor, wheres an EKG requires two sensors placed across the cross section of the heart. This is why when you need to measure the EKG on your Apple Watch, you need to touch one electrode with the hand that’s not wearing the watch to close the loop across the heart.

However the Apple Watch is capable of measuring heart rate without the need of the opposing hand’s touch as it uses Green and infra-red light sensors to measure the body’s PPG. This method is also followed by the dhyana ring.

I can almost hear your questions: If the method of measuring in the apple watch and the dhyana ring is the same, then why is the apple watch unable to measure HRV as consistently as the dhyana ring? Have the team of engineers at Dhyana done something that Apple could not? What is the underlying principle that makes dhyana better at measuring HRV? Also what is HRV?

Heart rate variability (HRV) is a measurement of the variations in time between consecutive pulses. If two pulses occur 1.00 seconds apart, then the next pulse arrives after 1.01 seconds, the variation is 0.01 seconds. While this seems small and insignificant, the purpose of these variations is vitally important. They give us a non-invasive insight into the functioning of the ANS and hence of the person’s psychological and physiological profile, for example you can tell the difference between a relaxed doctor and their temperamental and irritable wife by simply tracking their HRV.

Dhyana seems to measure HRV better than most other wearables simply because its worn on the finger. To know why the finger is better, lets get to know what PPG is.

The light you see shine from the wearable onto your body, whether green, red or infrared, light up that appendage of your body like a room. Once lit, a small light sensor sees what’s happening on the inside from a fixed position. Imagine a baby camera placed atop a shelf, and the baby camera can now see how often nutrition rich blood enters the room, and when it leaves the room.

Most wearables are worn on the wrist, and physiologically the wrist is a hard place to measure heart rate accurately using PPG. The wrist is a complex area, filled with thick tissue, and containing many moving parts such as joints, ligaments, tendons and muscles apart from a rich network of blood vessels. Imagine the baby camera on the shelf, but now you place moving objects in front of it. Monitoring the flow of blood becomes much harder. You may notice it every time the objects around stop moving, but once they start moving again, they consistently obfuscate the vision of the baby camera. To combat this, most wrist worn devices don’t calculate heart rate as the number of times nutritious blood enters the room, rather estimate heart rate based on predictive models such as the Kalman filter.

The finger is however very different to the wrist. It contains thin skin tissue and is a single bone surrounded by a rich network of blood vessels. Catching the blood entering and leaving the room becomes much easier when there aren’t so many moving parts.

This allows dhyana to use a small amount of energy, a hundredth of the ones that Apple Watches and FitBits use, to measure heart rate. Since it’s consistently tracking how often the heart beats rather than using predictive models, its capture of HRV is even more safe, accurate and reliable than a stopwatch wielding doctor who’s ear is at a patient’s chest.

How does Dhyana measures HRV

Article by: Bhairav Shankar

Measuring the rate of a patient’s heart beat is a pretty simple procedure and requires almost no tools or electronic whatsoever. One can measure it as simply as placing one’s ear against a patient’s chest while staring at a clock. Apart from the misfortune of being caught in this compromising position, the place-ear-against-chest method does suffer from a few further issues. The count can be interrupted with something as small as a cough, and measuring one’s heart rate for long durations of time, would require placing one’s ear affixed against a patient’s chest for said lengthy durations, an unpleasant feeling at the very least. To save their children’s chest from having a head attached to it, scientists across the world came up with new and innovative methods to measure heart rate.

But why is measuring heart so important?

The heart has played an important role in understanding the body since antiquity. In the fourth century B. C., the Greek philosopher Aristotle identified the heart as the most important organ of the body, the first to form according to his observations of chick embryos. It was the seat of intelligence, motion, and sensation – a hot, dry organ. Aristotle described it as a three-chambered organ that was the center of vitality in the body. Other organs surrounding it (e.g. brain and lungs) simply existed to cool the heart.

Science has advanced a bit from the time of Aristotle. For one thing, the heart has now been retconned to be as a muscle which thermoregulates the body and provides nourishment to all parts of the body by being the central engine that runs the circulatory machine. The heart is the most used indicator for proof of life, and its poor health is now the leading cause of death across the world.

Figuratively the heart now can be cold too, much like the one that a doctor could accuse their wife of having when their wife didn’t save any dinner for the doctor who’s spent the whole day saving lives, albeit by placing their ear to patients’ chests due to a faulty stethoscope.

However before one delves into how heart rate is measured automatically with the use of devices, it’s important to understand how the heart beats and what the biological consequences of such beating are.

The sinoatrial node (SAN) in the heart regulates the heart’s pumping, by sending a small electric impulse that commands the muscles in the heart to either relax or tense. The SAN is controlled by the Autonomic Nervous System (ANS), and hence the beating of heart changes depending on the state of one’s ANS. For example, a relaxed ANS would be considered to be parasympathetic and it commands the heart to beat at seemingly regular and slow intervals, however when the ANS is stressed it would be called sympathetic and is characterised by a heart that is beating much faster and is who’s consecutive beats arrive at more unpredictable intervals.

The ANS commands the heart to pump the blood via the SAN, the heart pumps oxygen and nutrition filled blood to all parts of the body. And when the SAN commands the heart to relax, the blood returns back to the heart after depositing all its nutrition and collecting any waste.

Scientists measure the heart at various points via multiple methods: electrocardiography, ballistocardiography, photoplethysmography, echocardiography and so on. The two predominant ones used by engineers are scientists across the world to measure heart rate are electrocradiography (EKG) and photoplethysmography (PPG).

EKG measures the electrical signatures around the torso, and in specific the functioning of the SAN. Heart rate from an EKG counts the number of times the SAN is activated in a minute.

PPG measures the pressure of the blood via optical sensors and checks how often nutritious blood reaches a peripheral in the body every minute.

The main advantage that permits PPG to be used in most wearable devices is because PPG requires only one sensor, wheres an EKG requires two sensors placed across the cross section of the heart. This is why when you need to measure the EKG on your Apple Watch, you need to touch one electrode with the hand that’s not wearing the watch to close the loop across the heart.

However the Apple Watch is capable of measuring heart rate without the need of the opposing hand’s touch as it uses Green and infra-red light sensors to measure the body’s PPG. This method is also followed by the dhyana ring.

I can almost hear your questions: If the method of measuring in the apple watch and the dhyana ring is the same, then why is the apple watch unable to measure HRV as consistently as the dhyana ring? Have the team of engineers at Dhyana done something that Apple could not? What is the underlying principle that makes dhyana better at measuring HRV? Also what is HRV?

Heart rate variability (HRV) is a measurement of the variations in time between consecutive pulses. If two pulses occur 1.00 seconds apart, then the next pulse arrives after 1.01 seconds, the variation is 0.01 seconds. While this seems small and insignificant, the purpose of these variations is vitally important. They give us a non-invasive insight into the functioning of the ANS and hence of the person’s psychological and physiological profile, for example you can tell the difference between a relaxed doctor and their temperamental and irritable wife by simply tracking their HRV.

Dhyana seems to measure HRV better than most other wearables simply because its worn on the finger. To know why the finger is better, lets get to know what PPG is.

The light you see shine from the wearable onto your body, whether green, red or infrared, light up that appendage of your body like a room. Once lit, a small light sensor sees what’s happening on the inside from a fixed position. Imagine a baby camera placed atop a shelf, and the baby camera can now see how often nutrition rich blood enters the room, and when it leaves the room.

Most wearables are worn on the wrist, and physiologically the wrist is a hard place to measure heart rate accurately using PPG. The wrist is a complex area, filled with thick tissue, and containing many moving parts such as joints, ligaments, tendons and muscles apart from a rich network of blood vessels. Imagine the baby camera on the shelf, but now you place moving objects in front of it. Monitoring the flow of blood becomes much harder. You may notice it every time the objects around stop moving, but once they start moving again, they consistently obfuscate the vision of the baby camera. To combat this, most wrist worn devices don’t calculate heart rate as the number of times nutritious blood enters the room, rather estimate heart rate based on predictive models such as the Kalman filter.

The finger is however very different to the wrist. It contains thin skin tissue and is a single bone surrounded by a rich network of blood vessels. Catching the blood entering and leaving the room becomes much easier when there aren’t so many moving parts.

This allows dhyana to use a small amount of energy, a hundredth of the ones that Apple Watches and FitBits use, to measure heart rate. Since it’s consistently tracking how often the heart beats rather than using predictive models, its capture of HRV is even more safe, accurate and reliable than a stopwatch wielding doctor who’s ear is at a patient’s chest.

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Dhyana is made in India by Avantari
+91 9346 2056 75 | support@smartdhyana.com



Accepted payment methods:

Cards

Paypal

Dhyana is made in India by Avantari
+91 9346 2056 75 | support@smartdhyana.com



Accepted payment methods:

Cards

Paypal

Connect with us:

Dhyana is made in India by Avantari
+91 9346 2056 75 | support@smartdhyana.com