Can Smartwatches Detect a Heart Attack? ECG and Rhythm Tracking

While smartwatches and digital health apps can track your heart rhythm and catch certain irregularities, they cannot definitively detect a heart attack. These devices are highly useful screening tools for noticing heart rate changes and rhythm disorders like atrial fibrillation. However, if you have complaints such as chest pain, shortness of breath, or pain radiating to your left arm, you should always trust the signals your body gives—not the technology on your wrist—and seek emergency medical help without wasting time.

At a Glance

• Smartwatches cannot diagnose a heart attack (infarction) caused by blocked arteries.
• Wearable technologies are quite successful at tracking high heart rates and rhythm disorders.
• Apple Health and similar apps can provide warnings for suspected atrial fibrillation (AFib).
• An ECG taken from the wrist is no substitute for a comprehensive 12-lead ECG taken at a hospital.
• In emergencies like chest pain, you must call 112 immediately without waiting for watch data.

What is Wearable Technology and Heart Tracking?

Smartwatches and wristbands, which have become an inseparable part of our lives in recent years, primarily work using optical heart rate sensors. You may have noticed the flashing green lights on the back of your watch. This technology, called photoplethysmography (PPG), measures changes in blood volume in your veins by shining light into your skin. Every time your heart beats, blood flow in your wrist increases, and the sensor detects this change to calculate your pulse.

With the advancement of technology, devices have been developed that not only count your pulse but can also take an electrocardiogram (ECG). These devices read the electrical signals produced by your heart when you touch your finger to the watch's crown or a special sensor. This data is then recorded and analyzed via digital health apps on your phone.

Especially when living in a fast-paced city like Istanbul, tracking our daily step count, sleep quality, and heart rate gives us a general idea about our health. Seeing how your pulse changes while rushing up the stairs to get to work in the morning or during a stressful meeting helps you know your body better. However, it is essential to know that this data is not a medical diagnostic tool, but merely a guide for monitoring your health.

Can Smartwatches Detect a Heart Attack?

Many people believe the smartwatch on their wrist will instantly notify them of any heart-related issue. In reality, smartwatches cannot detect a heart attack (myocardial infarction). A heart attack occurs when one of the coronary arteries feeding the heart is suddenly blocked, leaving the heart muscle damaged due to a lack of oxygen. This blockage may not always cause an immediate and obvious change in the heart's electrical system or pulse rate.

A person's pulse might be beating within completely normal limits while they are having a heart attack. Smartwatches only measure the heart rate and superficial electrical rhythm; they cannot see blockages inside the arteries, impaired blood flow in the heart muscle, or tissue damage. Therefore, even if your watch says "your heart rhythm is normal," if you feel pressure in your chest, you must believe your body, not your watch.

Protecting your heart health and minimizing the risk of a heart attack is possible through lifestyle changes, not just technological devices. To get more detailed information on this topic, you can review our article titled How to Prevent a Heart Attack? Symptoms and Risk Factors to learn about the signals the body gives before an attack and ways to protect yourself.

Arrhythmia and High Heart Rate Tracking

The area where smartwatches truly shine is the detection of heart rhythm disorders (arrhythmias) and unexplained high heart rates. Under normal conditions, a resting adult's heart beats between 60 and 100 times per minute. When you exercise, get excited, or drink a strong cup of Turkish coffee, it is completely physiological and expected for your pulse to rise.

However, if your pulse suddenly spikes above 120 or beats irregularly while you are resting on your sofa making no physical effort, it could indicate a problem. This is where Apple Health heart rhythm notifications or other Android-based health apps come into play. These apps continuously analyze the time between your heartbeats.

If the time between beats is constantly changing, the device may send you a "Suspected Atrial Fibrillation (AFib)" alert. Atrial fibrillation is a condition where the upper chambers of the heart quiver irregularly and rapidly. If left untreated, this rhythm disorder can lead to blood clots in the heart and a stroke. Smartwatches can play a life-saving role by catching this insidious rhythm disorder—which often presents no symptoms—at an early stage before you even go to the hospital.

Is a Smartwatch ECG Reliable?

One of the most frequently asked questions by users is "Is a smartwatch ECG reliable?". The ECG taken by smartwatches is a single-lead (single-channel) measurement. In other words, it only looks at the heart's electrical activity from a single angle. A standard ECG taken at a hospital, on the other hand, examines your heart from 12 different angles using electrodes placed on your chest, arms, and legs.

A single-channel ECG is quite successful at detecting obvious rhythm disorders like atrial fibrillation and has shown high accuracy rates in clinical studies. However, it is impossible to see damage to the back wall of the heart, valve problems, or thickening of the heart muscle from a single angle. For this reason, a smartwatch ECG should be considered a "screening" tool, not a "diagnostic" tool.

Furthermore, there is a possibility of the device giving false alarms. Having a sweaty wrist, a loose watch band, or moving or talking during the measurement can cause interference (artifacts) on the ECG graph. This interference can be interpreted by the app as a rhythm disorder. If you receive consecutive alerts, the best approach is to repeat the measurement in a quiet environment in the correct position without panicking, and if the result persists, consult a cardiologist.

Mistakes Made When Using Digital Health Apps

Although having technology track our health is a great advantage, digital health apps can sometimes lead to unnecessary anxiety and incorrect behaviors. Foremost among the most common mistakes is over-relying on the device's data. It is life-threatening for someone experiencing chest pain to delay going to the hospital by saying, "My watch shows my pulse is normal, so there's nothing wrong with my heart."

Another common problem is cyberchondria, an obsession with constantly checking health data. Stress hormone levels increase in people who measure their pulse every ten minutes throughout the day and obsess over their sleep data. Stress naturally raises the pulse and causes palpitations. As the person sees their high pulse, they become more stressed, creating a vicious cycle.

When using smart devices, it is necessary to accept that this data is merely a set of clues. Instead of trying to diagnose yourself by searching the internet for notifications like "low cardiovascular fitness level" or "irregular rhythm" given by the apps, you should use this data like a notebook to share with your doctor.

When Should You Trust Your Body, Not Technology?

Our body usually gives very strong signals when something is wrong. When these signals appear, what the watch on your wrist says is completely irrelevant. Especially when it comes to symptoms suspected of being a heart attack, even seconds are valuable, and waiting for technological verification is a waste of time.

If you experience one or more of the following symptoms, you should not wait for your smartwatch to take an ECG or try to analyze the graphs in the apps:

• A feeling of pressure, squeezing, or burning in the middle of your chest, as if a heavy stone is sitting on it.
• Severe pain starting in the chest and radiating to the left arm, jaw, neck, or back.
• Cold sweating and a fear of death suddenly appearing alongside the pain.
• Shortness of breath that feels like suffocating, developing while making no physical effort.
• Unexplained dizziness, blackout, and a feeling of fainting.

These symptoms are the clearest indicators that your heart is not getting enough oxygen. Especially in diabetic patients, the elderly, and women, heart attack symptoms can be milder or appear simply as nausea or a slight ache in the back. Seeking medical help whenever you have a doubt saves lives.

When to See a Doctor and Call 112

Knowing the difference between when to schedule a routine appointment for your heart health and when to call the emergency room is crucial. If you constantly receive a high heart rate alert from your smartwatch while resting, or if the app has sent you a "Suspected Atrial Fibrillation" notification several times, you should make an appointment with a cardiologist as soon as possible without panicking.

During routine examinations, your doctor will listen to your complaints, perform comprehensive tests in a hospital setting, and clarify whether the warnings given by your watch belong to a real rhythm disorder. Although such situations do not require emergency intervention, they are conditions that should not be neglected and require treatment planning.

However, if you have complaints such as chest pain, shortness of breath, cold sweating, and pain radiating to the jaw, as mentioned in the section above, you should definitely not try to go to the hospital in your own vehicle or wait for a relative to take you. The only thing you need to do in this situation is to call the 112 Emergency Call Center immediately. As soon as the ambulance teams reach you, they will take your first ECG, start intervention on the way if necessary, and transport you directly to a fully equipped center where an angiography can be performed.

The Cardiology Process at BHT CLINIC

For any doubts or complaints regarding your heart health, we are by your side at BHT CLINIC İstanbul Tema Hastanesi. When you apply to our Cardiology department with an arrhythmia alert you received from your smartwatch or a complaint of palpitations, our specialist physicians will first take a detailed medical history.

In our outpatient clinic, unlike the single-channel measurement of your watch, a standard ECG is taken, which evaluates your heart from 12 different angles. Echocardiography (heart ultrasound) is performed to see the condition of your heart valves and heart muscle. When necessary, a Holter monitor is attached to continuously record your heart rhythm during your daily life for 24 or 48 hours. If there is a suspicion of vascular occlusion, a definitive diagnosis is made using modern and comfortable methods such as a stress test or angiography from the wrist.

Our hospital is a center you can safely apply to in moments when seconds matter, with its fully equipped emergency department providing 24/7 uninterrupted service against sudden heart attacks and rhythm disorders, its coronary intensive care unit, and its angiography laboratory.

Frequently Asked Questions

Can smartwatches measure blood pressure?

Although some new-generation smartwatches claim to measure blood pressure, these devices cannot yet replace traditional blood pressure monitors that measure by inflating a cuff on the arm. Watches generally provide an estimated value using optical sensors. Blood pressure patients must monitor their condition using medically approved devices that measure from the arm.

What should I do if I get an Apple Health heart rhythm alert?

If the app gives you an atrial fibrillation or irregular rhythm alert, first stay calm. Repeat the measurement in a quiet environment without moving. If the warning persists, save the ECG PDF file recorded by your watch to your phone and consult a cardiologist as soon as possible.

Is a high heart rate alert always dangerous?

No, a high heart rate is not always a sign of illness. Exercising, experiencing a stressful moment, having a feverish illness, or consuming too much caffeine will raise your pulse. However, if your pulse is consistently above 100 while resting and for no apparent reason, you should see a doctor to find the underlying cause.

Is a smartwatch ECG the same as a hospital ECG?

It is definitely not the same. Smartwatches perform a single-lead (single-channel) measurement and only give an idea about rhythm disorders. A hospital ECG, on the other hand, is 12-lead; it shows the different walls of the heart, signs of vascular occlusion, and heart muscle thickening in detail.

Does a smartwatch give a warning during a heart attack?

Most of the time, no. A heart attack is a blocked artery problem and cannot be detected by smartwatches unless it causes a rhythm disorder. If you have complaints such as chest pain, pain radiating to the left arm, and cold sweating, emergency help should be called immediately regardless of your watch's data.

Click here to book an appointment with the Cardiology Department at BHT CLINIC İstanbul Tema Hastanesi.

This article is for informational purposes only; please consult your physician for diagnosis and treatment.