From tracking steps, sleep, stress, blood oxygen and even offering ECG scans right from the wrist, smartwatches are no longer the step-tracking tool they used to be. They are now marketed as mini health labs.
With this rise in wearable health tech blurring lines between health and medical issue monitoring, it got me wondering if a smartwatch can detect early signs of a heart problem, or at least warn someone before something goes wrong?
The short answer is: no, smartwatches can’t diagnose most heart issues, nor can they replace medical devices, but they can still be helpful in catching signals, especially arrhythmias like AFib. Here’s what they can and can’t do, and how to use them safely.
What Smartwatches Can Detect
Irregular Heart Rhythms
An area where smartwatches truly shine is detecting irregular heart rhythms and especially AFib. A recent study shows that smartwatches can detect AFib with ~94-97% accuracy and they excel at alerting to possible AFib.
They even track episodes over time and can record an ECG to be shared with your doctor.
Resting Heart Rate
Smartwatches are also great tools for alerting you if your resting heart rate is unusually high or low.
HRV Trends
They also record HRV trends over time that indicate a poor recovery, overtraining, illness, stress or sleep issues.
Lifestyle Metrics that Affect Heart Health
Because smartwatches and other wearables help in tracking trends over time- be it sleep, stress, activity, VO2 Max, recovery or HRV, they make a great predictor of your health and wellness.
We can easily identify what lifestyle change triggered a shift in our metrics.
What Smartwatches Can’t Detect
They cannot detect a Heart Attack
One of the major heart problems, such as a heart attack, cannot be predicted by a smartwatch. This is because a heart attack involves blocked arteries, not rhythm changes.
Since smartwatches offer single-lead ECG (on-demand), they cannot detect ST-segment elevations or ischemia like a clinical 12-lead ECG.
Diagnose Heart Disease
To detect major heart diseases, clinical procedures and tests such as CT scans, MRIs and echos are required. These procedures can help detect valve issues, congenital defects, heart muscle weakness, coronary blockages, etc, that can diagnose a heart disease.
Smartwatches can help with general health monitoring, but cannot predict or diagnose diseases.
Misses Short Arrhythmias
If an arrhythmia event lasts a few short seconds and you’re not recording an ECG, it is often missed and not detected by a smartwatch.
Produce False Alarms
Smartwatches’ PPG sensors are often affected by external factors such as sweat, tattoos, movement, loose strap and skin tone. This can either lead to a false positive or a missed event.
Cannot Interpret Symptoms
While the data from a smartwatch is extremely important, it is more important to notice how you feel, even if your smartwatch is not sending you an alert. In case of chest discomfort, breathlessness, fatigue or dizziness, it is best to listen to your body and consult a doctor to rule out any underlying issue.
How Smartwatches Detect Early Signs of Heart Problems
- Smartwatches capture silent AFib that goes unnoticed without a wearable monitoring the same. AFib is a major risk factor for stroke, so it can be very helpful in detecting it early.
- Because smartwatches collect data over time, the trends in resting heart rate, HRV and sleep can help reveal early signs of changes in your health.
- Wearables motivate people to move more, sleep better, keep a tab on their stress levels and improve overall fitness. All this ultimately helps in improving heart health.
- Because medical equipment can take a test only when you visit the hospital, the trend reports generated by smartwatches help the doctors look at the pattern to detect any potential signs of concern.
How to Safely Use a Smartwatch for Heart Monitoring
Dos:
- Use smartwatches to track trends, not single data points.
- Take an ECG reading if the watch prompts.
- Consult a doctor if an irregular heart rhythm alert appears
- Pay attention to whether you experience any symptoms, even if the watch does not give an alert.
- Share ECG and trend reports with your doctor.
Don’ts:
- Blindly rely on your smartwatch data.
- Ignore symptoms like breathlessness or chest pain.
- Let the data anxiety get to you.
- Self-diagnose based on your smartwatch data.
Wrap Up
Wearable tech has moved way beyond step count. We can take ECG readings right at our fingertips, monitor trends in our sleep patterns and HRV, and detect signs of AFib. While there are still certain limitations and they can’t explicitly diagnose a disease, smartwatches can be a helpful tool in analyzing changes in our health before a serious problem arises.
What’s next? New research is exploring AI-enhanced ECG analysis, prediction of heart disease using watch ECG patterns, continuous cuffless blood pressure monitoring, glucose estimation from wrist sensors and heart failure detection based on passive signals.
AI models are already identifying ECG signatures that may indicate a risk long before any symptoms appear. We are not there yet, but the next 3-5 years will change wearable heart monitoring drastically.
