While its original intention was not a focus on well-being, the Apple Watch has now become synonymous with health and fitness. There is one physical measure that the gadget has stuff since its release in 2014 though – Heart-rate and Ecg tracking.
While the heart rate isn’t actually the most reliable measure of a person’s cardiovascular health, it’s the simplest to measure, and can provide a basic indication of a possible medical condition. Apple has invested vigorously in medical innovation with an end goal to make the heart-ECG tracker as precise as could be expected under the circumstances.
And that tech also forms the backbone for the more technically-demanding ECG (electrocardiogram) tracking, which Apple incorporated in Apple Watch Series 4.
Taking care of your heart is easy with the “Apple Watch ECG app”, here’s how
PPG – The tech used to measure heart rate is similar to a pulse oximeter. The system illuminates the skin and measures change in light absorption as blood circulates.
An electrocardiogram is a little more complicated. This estimates your pulse’s, cadence, and electrical movement. ECG readings need to be as accurate as possible,
and this is one of the reasons it is taking Apple time to get the feature approved by the government and medical boards in a number of countries; currently, 40 countries have permitted the ECG feature on the Apple Watch. With Apple Watch Series 4,
Apple introduced a crystal electrode plate on the back of the Watch and on the Digital Crown for ECG measurements. With the Watch against your skin, you place your finger on the Digital Crown to create a closed (or full) circuit between both your hands.
The closed-circuit allows electrical impulses to flow through the Watch so that it can measure the impulses as they flow across your chest.
EXPLAINED… Taking an ECG reading
To set up ECG, open Health on your iPhone, and open the Heart option. You should see an option to Set Up ECG App. Follow the steps indicated. Once you have set up the app, you should see it appear on your Watch. If you don’t see the option, update to the latest iOS and watchOS.
B Take a Reading
To take a reading, open the ECG app and rest your arm on a table or your lap. With your opposite hand, hold your index finger on the Digital Crown, but do not press it. The recording takes 30 seconds, so for the best results, do not move during this reading time.
C View results
Once the test is completed, you can view results in the Health app on your iPhone. The app classifies results in Sinus Rhythm, Atrial
Fibrillation, Low or High Heart Rate or Inconclusive. You can export the results as a PDF to share with your doctor if you want.
Heart rate tracking
So now the science bit: photoplethysmography (PPG) is a method of detecting blood volume changes in a microvascular bed of tissue, allowing a heart rate to be measured noninvasively on the skin’s tissue.
And this is how the heart rate tracker on the Watch works. As indicated by Apple: “Blood is red” since it “reflects red light” and “ingests green light”. Apple Watch uses green LED lights paired with light-sensitive photodiodes to detect the amount of blood flowing through your wrist…
When your heart beats, the blood flow in your “Wrist – and green light retention” – is more prominent. Between beats, it’s reduced.
“Apple Watch”– can count the number of times the heart beats every moment By glimmering its “LED” lights several times each second”.
These LEDs and infrared diodes are housed in the clay back of the Watch. The infrared is the primary system and takes a reading every 10 minutes in the background even if the watch is not in use. The LEDs kick in as a fail-safe when the data from the infrared seems inconsistent.
The LEDs are used to measure heart rate during workouts, breathe sessions and heart rate variability (the variation in the time interval between two consecutive heartbeats) tests.
One of the biggest concerns over health smarts is accuracy. As they are not tested to the same standard as medical equipment used by professionals, devices like the Apple Watch cannot be used as a substitute for hospital tests.
Apple obviously expresses that the Watch isn’t 100% solid, saying: “considerably under perfect conditions, Apple Watch will most likely be unable to get a dependable pulse perusing each time for everyone.
Also, for a little level of people, different variables may make it difficult to get any pulse perusing whatsoever.” Some factors that can affect accurate readings include skin thickness, perfusion (the amount of blood flowing through your skin), tattoos, and taking part in sports that involve irregular movements (such as boxing, tennis, cricket, etc).
The Watch has to be on top of your wrist for the sensors to work, but Apple says the fit of the Watch can also affect readings. It’s also important to keep your Watch and skin clean and dry, as water and dirt can affect the sensors.
Apple has made significant improvements to the sensors over the years, and the Watch has been able to identify heart conditions for some users, which Apple has proudly mentioned in its keynotes.
Apple’s Health app already provides a comprehensive well-being overview, and the company is looking to expand its health-tracking features into related areas, such as blood pressure and glucose monitoring.