Wearable devices can track important health changes and provide early warning signs, but doctors say they can’t independently predict or diagnose the disease.
A smartwatch can quietly monitor your heartbeat while you sleep, alert you to an unusual heartbeat during the day, and even record an electrocardiogram (ECG) on some devices with the touch of a button. As wearable devices become increasingly sophisticated, they’re starting to look less like fitness tools and more like personal health monitors. But how much can they actually tell us about what’s going on inside the body?
Besides counting steps and calories, wearable devices are increasingly becoming part of the way people monitor their daily health. Its ability to continuously collect information gives users a record of how their bodies behave over hours, days and even weeks, rather than relying solely on occasional checks. Doctors say this longer look can sometimes reveal patterns that deserve more careful medical attention.
Health experts point out that these devices can report changes worth paying attention to, but they cannot predict or diagnose disease on their own.
Wearables have brought about a major shift from fitness-focused devices to health monitoring tools, said Dr Rachit Saxena, director and unit head, Yashoda Institute of Cardiac Sciences.
“Wearables have moved from fitness accessories to real health monitoring tools,” he said. “For patients and doctors, this is a remarkable shift. However, it comes with an important difference: monitoring is not the same as prediction.”
More of healthWearable devices can provide early warning signs
Doctors say constant monitoring can sometimes encourage people to seek medical care before symptoms become apparent.
Dr. Saxena said he has seen cases where wearable devices detected irregular heartbeats in people who had no symptoms, prompting them to seek medical evaluation.
“Sleep tracking data has helped identify patterns consistent with sleep apnea, which itself is a risk factor for high blood pressure and cardiovascular disease,” he said.
He added: “If used correctly, these devices act as an early warning system that encourages people to consult a doctor sooner rather than later.”
Wearable devices can continuously track several physiological measurements, including heart rate, blood oxygen saturation (SpO₂), respiratory rate and sleep duration, added Dr Abhijit Singh, Associate Director and Unit Head, ShardaCare-HealthCity.
“These metrics can provide valuable insights into trends that may indicate an early onset of respiratory or cardiovascular problems,” he said.
However, he stressed that wearable devices remain screening and health tools and not diagnostic devices.
“They can alert users to changes that require medical evaluation, but they cannot diagnose diseases independently,” he said.
What wearable data might indicate about lung health
For respiratory health, changes in wearable readings can sometimes provide clues that warrant further medical evaluation.
A persistent rise in resting breathing rate, unexplained drop in oxygen saturation during the night, poor sleep quality or high resting heart rate can indicate conditions including sleep apnea, exacerbation of asthma, chronic obstructive pulmonary disease (COPD), respiratory infections, or even premature heart failure, Dr. Singh said.
Sleep tracking can also highlight patterns associated with fragmented sleep or breathing disturbances during the night, which may prompt a person to seek medical advice.
Why can’t a smart watch diagnose disease?
Despite their growing capabilities, wearable devices have clear limitations.
A 1-lead EKG can indicate an arrhythmia, but it cannot confirm the diagnosis in the same way as a 12-lead EKG or echocardiogram, Dr. Saxena said.
“Heart rate variability trends may indicate stress or fatigue, but they cannot reliably predict a heart attack or stroke,” he said.
“Predicting disease requires clinical context such as family history, blood tests, imaging, and physician judgment. Algorithms and data cannot predict any disease.”
Dr. Singh also cautioned that readings can vary depending on several factors.
“Factors such as improper fit, skin pigmentation, movement during sleep or exercise, cold extremities, and the quality of the device can affect the readings,” he said.
Therefore, one unusual reading does not necessarily mean that a person is suffering from a medical condition.
Long-term trends matter more than a single reading
Doctors say the real benefit of wearable devices is collecting health data over time rather than relying on isolated measurements.
“If a person notices persistent low oxygen saturation, recurring episodes of high heart rate, worsening sleep patterns, or decreased ability to exercise over several days or weeks, a medical evaluation should be performed,” Dr. Singh said.
For people with chronic respiratory diseases, wearable devices may also help track changes in disease stability and encourage adherence to treatment and healthy habits.
Continuous, real-time data can complement clinical care by giving doctors additional information between appointments, Dr. Saxena said.
“The real value of wearables lies in continuous, real-time data that complements rather than replaces clinical care,” he said.
A healthcare tool, not a replacement
Both doctors emphasized that wearable technology works best when its data is interpreted alongside appropriate medical evaluation.
Dr Singh said wearable devices could help people become more health conscious, but their usefulness depended on how the information was understood.
“When combined with clinical expertise and appropriate medical evaluation, wearable technology has the potential to support early disease detection, improve disease monitoring, and enhance proactive respiratory care,” he said.
Dr. Saxena summed up the role of technology simply: “Wearables are a bridge to better healthcare, not a replacement for it.”
