Smartwatches, fitness trackers, rings, and other wearable devices have changed how people monitor their health.
Depending on the device, they may track:
Heart rate
Heart rhythm
Physical activity
Steps and movement
Sleep
Blood oxygen estimates
Cardiorespiratory fitness
Heart rate variability
Other wellness measurements
This information can be valuable because it provides observations outside the doctor's office and can reveal patterns that might otherwise go unnoticed.
The American College of Cardiology (ACC) has increasingly addressed the role of consumer wearables in clinical care. In August 2026, the ACC highlighted how clinicians can incorporate wearable information into cardiovascular conversations while recognizing its limitations.
But there is an important distinction:
A wearable can identify a signal. It does not necessarily explain the signal.
An alert from a smartwatch is not equivalent to an abnormal result from a medical diagnostic test.
Consumer wearables use sensors and algorithms that estimate physiological measurements. Their accuracy can vary depending on:
Device model
Sensor technology
How the device is worn
Movement during measurement
Skin contact
Activity level
Individual characteristics
The ACC has specifically cautioned that wearable measurements can be difficult to interpret because devices use different technologies, algorithms, and testing conditions.
Therefore, one unusual number should generally be considered a piece of information rather than a diagnosis.
Heart rate is one of the most commonly monitored wearable measurements.
You may notice that your resting heart rate is:
Higher than usual
Lower than usual
More variable
Increasing over several days
A change can occur for many reasons, including:
Exercise
Stress
Dehydration
Fever or illness
Poor sleep
Caffeine
Medications
Changes in fitness
The important question is whether the change is persistent, substantial, unexplained, or associated with symptoms.
A single elevated reading after climbing stairs means something very different from repeatedly elevated resting heart rates while sitting quietly.
This is one area where wearable technology has become particularly interesting.
Some devices can identify patterns suggestive of atrial fibrillation (AFib).
However, there is an important distinction between detecting a possible irregular rhythm and diagnosing AFib.
The FDA-authorized irregular rhythm notification technology, for example, is intended as a screening tool and is not intended to diagnose AFib or guide treatment on its own.
The ACC similarly notes that an irregular pulse notification does not itself establish a diagnosis of AFib.
If your wearable repeatedly reports an irregular rhythm—particularly if you also experience palpitations, dizziness, unusual fatigue, or shortness of breath—it is reasonable to discuss the findings with a healthcare professional.
A clinician may determine whether an ECG or another form of medical-grade rhythm monitoring is appropriate.
This is an equally important point.
People sometimes assume:
“My watch did not alert me, so my heart must be fine.”
That conclusion is not supported.
The absence of an alert does not rule out cardiovascular disease, and wearable devices do not detect every type of heart problem.
The ACC's 2025 guidance specifically notes that Apple Watch heart-health features should not be used when continuous clinical monitoring is indicated, and that the device cannot detect heart attacks.
Wearable technology should therefore complement—not replace—appropriate medical evaluation.
Some consumer devices estimate blood oxygen saturation (SpO₂) using optical sensors.
This can be useful for observing trends, but consumer wearable oxygen measurements have important limitations.
The ACC has reported that wrist-worn consumer devices using photoplethysmography for SpO₂ have generally shown poor accuracy and may overestimate oxygen saturation.
A single unexpectedly low reading can therefore result from measurement conditions rather than a genuine change in oxygenation.
However, persistent or significantly abnormal readings—especially when accompanied by shortness of breath, chest discomfort, confusion, or other symptoms—should not be dismissed simply because the device is consumer-grade.
Heart rate variability (HRV) has become increasingly popular in fitness and wellness tracking.
HRV reflects variation in the time between heartbeats and is influenced by the autonomic nervous system.
It can change with:
Sleep
Stress
Training load
Recovery
Illness
Alcohol
Other physiological factors
But HRV is particularly easy to overinterpret.
The ACC notes that wearable devices calculate HRV in different ways and that absolute HRV values are difficult to interpret clinically. Trends over time, considered alongside the person's clinical history, may be more useful.
In other words:
A low HRV score does not automatically mean that you are unhealthy.
Wearables can provide useful information about:
Sleep duration
Bedtime and wake time
Movement during sleep
Estimated sleep stages
But sleep-stage estimates are not equivalent to measurements obtained in a formal sleep study.
If you consistently feel exhausted despite apparently adequate sleep, or experience symptoms such as loud snoring, witnessed pauses in breathing, or significant daytime sleepiness, the issue may require clinical assessment rather than simply changing your wearable settings.
Wearables can also help identify gradual changes in physical activity and exercise capacity.
For example, over several months you might notice:
Fewer daily steps
Lower exercise frequency
Reduced estimated cardiorespiratory fitness
Increasing heart rate during activities that previously felt easier
Longer recovery after exercise
No individual measurement establishes a diagnosis.
But together, these changes can provide useful information to discuss with a healthcare professional.
The ACC recognizes potential value in wearable data for tracking cardiovascular health and supporting longitudinal conversations between patients and clinicians.
Consider two scenarios.
Your resting heart rate is 78 today.
That number alone provides limited information.
Your resting heart rate has increased gradually from your usual range over several weeks, while your activity has declined and you are experiencing unusual fatigue.
The second scenario provides considerably more context.
This is why personal baseline and change over time can be more useful than comparing one measurement with a generic internet “normal.”
Often, yes—particularly when you have a persistent pattern or a device has generated a clinically relevant alert.
When sharing the information, provide context:
What device recorded it?
When did it occur?
Were you resting or exercising?
How frequently has it happened?
What is your usual baseline?
Were you experiencing symptoms?
Were there recent changes in medications, sleep, illness, or activity?
The ACC's current approach emphasizes integrating wearable information into a broader clinical assessment rather than interpreting isolated data points independently.
Depending on the measurement and symptoms, a healthcare professional may:
Review the wearable data
Check whether the measurement is technically credible
Compare it with your previous readings
Review medications and medical history
Perform a physical examination
Repeat the measurement using a clinical device
Order targeted testing if appropriate
For example, a suspected rhythm abnormality might lead to an ECG or ambulatory monitor rather than simply accepting the smartwatch notification as the diagnosis.
Wearable data should never delay emergency care when significant symptoms are present.
Seek emergency medical attention for symptoms such as:
Chest pain or pressure
Severe or sudden shortness of breath
Fainting or near-fainting
Severe weakness
New confusion
Sudden neurological symptoms
A rapid or irregular heartbeat accompanied by significant symptoms
The appropriate response should be based on the person's symptoms and clinical condition, not simply on what a device reports.
There are two common mistakes with wearable health data.
“It's just a smartwatch, so it means nothing.”
This can overlook useful information, particularly when a persistent change corresponds with symptoms.
“My watch says something is wrong, so I definitely have a disease.”
This can lead to unnecessary anxiety and testing.
The better approach is:
Notice → Record → Contextualize → Discuss → Confirm when appropriate
The technology is moving rapidly.
The FDA continues to evaluate wearable technologies and their cardiovascular notification capabilities, while professional organizations such as the ACC are developing practical guidance for incorporating these technologies into patient care.
The direction of healthcare is therefore not toward ignoring wearable data.
It is toward using it more intelligently.
Wearables may be particularly useful for identifying changes between clinical visits, supporting behavior change, and providing additional information during conversations with healthcare professionals.
But the technology works best when its measurements are placed within the context of a person's symptoms, history, examination, and clinically validated testing.
Your smartwatch may tell you:
“Something changed.”
It may not be able to tell you:
“Why it changed.”
That distinction is central to using wearable health technology responsibly.
An unusual heart-rate trend, rhythm alert, sleep pattern, oxygen reading, or decline in activity does not automatically mean disease. But a persistent change—particularly one that corresponds with new symptoms—can be useful information worth discussing.
The goal is not to become dependent on every number your device produces. It is to use technology as another source of health information, while allowing clinical evaluation to determine what that information actually means.
Wearable health data can be valuable, but abnormal does not automatically mean diagnostic.
Pay particular attention when a reading:
Is repeatedly abnormal
Represents a significant change from your normal baseline
Continues over time
Occurs alongside symptoms
Relates to a clinically important measurement such as heart rhythm
Use the data as a conversation starter—not a substitute for medical care.
The most useful question is not simply “Is this number normal?”
It is:
“Is this a meaningful change for me, and does it need to be confirmed clinically?”
