What wearables can (and cant) tell you about your health and when its time to see a doctor
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Not all smartwatch health data is created equal. Wearables are great at showing trends like steps and activity, but many popular metrics can be inconsistent and easily affected by everyday factors.
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Consumer wearables arent medical-grade devices. Unlike clinical equipment, smartwatches arent built or tested to meet strict medical standards, which means their readings shouldnt be used to diagnose health conditions.
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Use wearables as a signal, not a verdict. Sudden or unusual changes in your data are a reason to talk to a doctor not to self-diagnose since smartwatch metrics are meant to inform, not replace, professional care.
January is prime time for health resets. New routines, new goals, and for many people, a new wearable device promising deeper insight into everything from heart rate to sleep quality.
These devices can be motivating and informative but experts say theyre often misunderstood, especially when it comes to how much trust consumers place in the numbers on their screens.
To better understand where smartwatch health data shines and where it falls short ConsumerAffairs spoke with two experts who work behind the scenes of medical and electronic devices Leon Huang, CEO of RapidDirect, a company that supports medical device manufacturing and validation, and Hommer Zhao, founder of WellPCB and an expert in medical electronics production.
Consumer smartwatches and medical-grade devices
One of the biggest things that the experts are encouraging consumers to recognize is that there is a big difference between consumer smartwatches or rings and medical-grade devices.
"The biggest difference between these devices is how they are designed, tested and validated, Zhao said.
Medical-grade devices are built to operate within strict accuracy tolerances under a wide range of conditions, with documented testing, traceability, and regulatory oversight. Consumer smartwatches use simplified sensors and algorithms optimized for comfort, battery life, and cost. Theyre very good at showing trends; however, theyre not designed to meet the same consistency or verification standards required in clinical settings.
The metrics to track
While your wearable device of choice may inundate you with tons of personal health information, the experts warn that not every stat is as accurate as it seems.
Step counts and general activity tracking tend to be the most reliable because motion sensing is a mature technology, Zhao said. Resting heart rate trends can also be useful when viewed over time.
On the other side, metrics like sleep stages, blood oxygen, and stress scores are far more variable, as theyre heavily affected by movement, fit, skin temperature, and signal noise. People often assume all metrics are equally accurate, which isnt always the case.
Additionally, certain factors can make readings more or less accurate.
Cold weather, loose fit, excessive movement, darker tattoos under sensors, dehydration, and even sleeping position can all interfere with readings, Zhao said. These factors are common in everyday life, which is why consumer wearables struggle to deliver consistent accuracy across users and conditions.
When is it time for a doctors visit?
So, if you regularly wear a smartwatch or ring, how do you know when your metrics indicate a problem that should be checked out by a medical professional?
If your wearable highlights a sudden or persistent change, examples like irregular heart rhythms, unusual fatigue or breathing issues, thats a prompt to see a professional already, and not to self-diagnose, Huang said. Our smartwatches are good at raising flags, but interpretation and diagnosis should still belong in a clinical setting.
Huang also explained that these readings have been found to impact when consumers seek professional medical care.
False reassurance can delay people from seeking care, while false alarms can cause unnecessary anxiety, he said. These metrics should always be treated as informational, and not diagnostic.
Health support
The experts encourage consumers not to get rid of their smart devices. Instead, focus on the ways that they can support your healthy habits.
Smartwatches are useful tools when people understand their limits, Zhao said. The problem is the assumption that consumer devices offer clinical certainty.
When used correctly, wearables can support healthier habits and awareness, but they should never replace professional medical advice.
Posted: 2026-01-23 20:05:41
