What began as a way to count steps and track workouts is rapidly becoming something much bigger. Smartwatches, rings, fitness bands, and other wearable devices are now being viewed as powerful tools that may help identify illness before symptoms even appear. Technology companies are investing billions of dollars into the idea that wearable devices, combined with artificial intelligence, could eventually predict diseases, warn users of medical emergencies, and help doctors monitor chronic conditions in real time.
The wearable health market has already grown into an industry worth more than $90 billion. Companies such as Apple Inc., Samsung Electronics Co., Alphabet Inc., Oura Health Oy, Whoop Inc., Garmin Ltd., and Philips are all racing to turn consumer devices into predictive health platforms.
What Wearables Actually Measure
Modern wearable devices collect a surprising amount of biometric information. Smartwatches and rings can monitor heart rate, resting heart rate, blood oxygen levels, sleep duration, respiratory rate, step counts, skin temperature, and heart rate variability, often called HRV. Some devices can also collect ECG signals to identify irregular heart rhythms such as atrial fibrillation.
These measurements are made possible through sensors such as photoplethysmography optical sensors, which measure changes in blood flow and capillary volume. Devices also use motion sensors to measure activity levels and gait.
Companies believe these data streams can reveal subtle changes in the body that happen before a person feels sick. As Oura CEO Tom Hale explained, “The real breakthrough isn’t knowing you had a problem. It’s knowing before you do, so you can change behavior and prevent it.”
What Conditions Can Be Detected or Predicted
Wearable technology is already being used to help identify several important medical conditions. Heart disease is one of the biggest targets. Researchers and companies are working on systems that can detect warning signs of heart attacks, strokes, hypertension, and arrhythmias long before a crisis occurs.
Studies involving devices from Apple and Fitbit have already shown that wearables can help identify previously undiagnosed atrial fibrillation cases. AI systems analyze enormous numbers of biometric data points and learn to distinguish between harmless fluctuations and possible danger signs.
Other conditions being studied include diabetes, hormonal changes, fertility, menopause, dementia, and infectious diseases. Samsung Health is developing systems that look for early signs of dementia through speech patterns and gait analysis. Oura has introduced features related to menstrual cycles, birth control monitoring, ovulation prediction, and menopause tracking. Garmin partnered with Natural Cycles to improve ovulation prediction using skin temperature data.
The field is also expanding into chronic inflammatory diseases. A major rheumatoid arthritis study published in Scientific Reports showed that wearable devices could detect physiological changes associated with rheumatoid arthritis flares up to four weeks before symptoms appeared.
Researchers tracked participants using Apple Watches, Fitbit devices, and Oura Rings. They discovered that inflammatory flare periods were linked to higher heart rates, increased resting heart rates, altered heart rate variability, and reduced physical activity. The study concluded that wearable devices could support “early flare prediction and proactive clinical management.”
Real Cases Where Wearables Helped Save Lives
Some of the strongest arguments for wearable technology come from real-world examples.
Haley Billey originally purchased an Oura Ring to track fertility, but unusual stress and energy readings eventually pushed her to seek medical advice. Doctors later diagnosed her with Hashimoto’s disease, an autoimmune disorder. “I can look at the data and take it to my doctor,” she explained.
Another Oura user, Thomas Lynch of Florida, credited his ring with helping save his life after surgery. The device detected an elevated heart rate, which ultimately led doctors to diagnose a pulmonary embolism.
Researchers studying rheumatoid arthritis found that wearable-derived physiological changes consistently appeared weeks before inflammatory and symptomatic flares. The study reported extremely high predictive performance scores for identifying flare development as far as 28 days in advance.
Billions of Dollars Are Pouring Into the Industry
The financial stakes are enormous. Whoop was valued at $10.1 billion after raising $575 million in a financing round. Oura reached a valuation of roughly $11 billion after raising $875 million.
Tech companies are betting that wearable devices will eventually evolve from wellness products into health prediction platforms. Fitbit has already integrated medical records and continuous glucose monitor readings into its systems, while AI tools are being designed to recommend interventions based on detected risks.
Will Ahmed, CEO of Whoop, described the ambition this way: “The same way a large language model predicts the next word, we’re building models that can predict the next heartbeat.”
The Military Is Deeply Interested
The U.S. military is also investing heavily in wearable disease prediction systems. The Department of Defense and the Defense Innovation Unit developed the Rapid Assessment of Threat Exposure program, known as RATE, during the COVID-19 pandemic.
RATE used AI algorithms trained on hospital-acquired COVID-19 data and biometric readings from commercial wearable devices. According to the Department of Defense, the system was able to detect infectious diseases up to 48 hours before symptoms appeared, and in some cases as much as six days before onset.
Jeff Schneider, the RATE program manager, said, “With RATE, the DOD can use commercial wearables to noninvasively monitor a service member’s health and provide early alerts to potential infection before it spreads.”
The Pentagon has continued expanding the program with additional funding and thousands of additional users. Garmin watches and Oura Rings are among the devices being deployed.
Military leaders see the technology as a readiness tool that could reduce outbreaks and improve troop health. Philips is helping develop the algorithms and hopes to commercialize the technology on a broader scale.
Concerns About Privacy and Reliability
Despite the excitement, experts continue to warn that wearable technology is not yet ready to replace doctors or clinical-grade medical devices.
False positives can cause anxiety and unnecessary medical testing. False negatives may provide false reassurance. Some researchers worry that people could become obsessed with constantly monitoring themselves.
There are also major privacy concerns. Much of the data collected by wearable companies may fall outside traditional HIPAA protections and instead be governed by company terms of service agreements. Cybersecurity experts worry that health data could eventually be used for targeted advertising or other secondary purposes.
Dr. N. Murali Krishna cautioned that wearable technology should still be viewed as “a supplement, not a substitute for regular medical care, clinical-grade monitoring devices, and healthy living.”
Still, the momentum behind wearable health technology continues to grow rapidly. Researchers, corporations, and governments increasingly believe that continuous biometric monitoring may someday transform medicine from a reactive system into one focused on prevention and early intervention. For millions of people, the smartwatch or ring on their finger may eventually become one of the first warning systems for serious disease.
