Your smartwatch might know you’re sick before you do—and it might help stop pandemics

Smartwatch features that measure heart rates, oxygen levels, fitness levels and sleep quality have been marketed as valuable tools for people who are eager to monitor their health.

But what if these features could do more than detect potential health issues—what if they could prevent potential health disasters such as pandemics?

Recent studies have demonstrated that smartwatches’ health apps and sensors provide enough information to accurately predict when a person has become infected with a disease like COVID-19 or the flu, even within as few as 12 hours after infection.

In a study published this March in PNAS Nexus, researchers at Texas A&M University and Stanford University used a computational model to estimate how smartwatch-based detection could help control the spread of pandemics such as COVID-19 and pandemic influenza.

Their findings suggest that smartwatch detection could lower pandemic transmission risk by nearly 50% by providing early warnings to people with potential infections, prompting them to isolate and greatly lowering their chances of spreading disease.

“Even before a person starts showing symptoms of disease, there are physiological changes that happen to their body—like an increase in temperature or a change in sleeping pattern—that are usually too subtle for a person to notice but that can be detected by a smartwatch,” said Dr. Martial Ndeffo-Mbah, an assistant professor in the Texas A&M College of Veterinary Medicine and Biomedical Sciences’ (VMBS) Department of Veterinary Integrative Biosciences.

As a result, if used at scale, smartwatches could effectively end pandemics before they begin by warning people to take precautions—including getting an official diagnosis through traditional testing—much earlier in the infection cycle than they would normally.

“Research on influenza from the Centers for Disease Control and Prevention indicates that most people initiate treatment quite late, many days after the onset of symptoms, when they should ideally begin treatment before symptoms begin,” Ndeffo said. “Even in the presymptomatic stage, infected individuals are often contagious; studies have shown that as much as 44% of COVID-19 infections were transmitted by presymptomatic individuals.”

Using smartwatches, then, could make the problem of disease transmission more personal and encourage more people to take practices like isolating and getting tested more seriously, increasing the overall efficacy of existing tools.

“The protocols for COVID-19 included steps like isolating even after being in contact with someone who is sick, but many people tend to ignore that advice if they don’t feel sick themselves,” Ndeffo said. “With a smartwatch, you could find out in real time—with a high degree of accuracy—if you are starting to get ill, which would hopefully give you a stronger motivation to follow protocols.

“Additionally, while we focused our recent publication on two respiratory diseases, there is a lot of potential to use smartwatches as a preventative tool for many other illnesses, including RSV,” he said. “Whenever the immune system responds to infection, there will be physiological changes that a smartwatch could help detect.”

Transforming disease diagnosis

Testing remains one of the most important tools for stopping the spread of disease because people are more likely to take precautions once they have a diagnosis. But even with high-quality tests easily available to most people, there is room for improvement.

“During the COVID-19 pandemic, at-home testing kits became very popular, which is a good thing because they’re a great public health tool,” Ndeffo said. “But there is a problem with how they are used—people might only use a test if they feel sick or are about to travel, and they probably only test themselves once. That’s not frequent enough to catch every infection, especially if you want to catch them early.”

Early detection with smartwatches could be the key to catching more infections, and it can also prompt people to seek early treatment.

“If you can seek treatment early, you may be able to prevent the worst symptoms from occurring, which is particularly important for high-risk and immunocompromised individuals,” Ndeffo said.

Creating a personal stake in prevention

One of the challenges of developing new public health tools is motivating large numbers of people to comply with disease-prevention protocols.

“If you wake up in the morning and feel a little tired, you’re probably not going to assume that you need to get tested for COVID-19 or the flu, especially when some of the tests involve nose swabbing and other hassles,” Ndeffo said. “So, we are considering how smartwatches may give people more information that will help them see the benefits of reducing contact and getting tested. We hope it will reach people who are not reached by traditional testing alone.”

While research teams are already making headway toward being able to use smartwatches on a large scale for disease prevention, there is still work to be done.

“Teams are working on the science and epidemiology side, and developers are working on the technology,” Ndeffo said. “Because there is so much potential good that this technology can do, we are working hard to make sure we get it right.”