What the Galaxy Watch 5 Next-Level Health Tracking Means For Apple Watch

At its Unpacked event in August, Samsung debuted its new Galaxy Watch 5, offering several small design tweaks and one big new health-tracking feature: measuring changes in skin temperature. Only time will tell whether it ends up being a killer feature the upcoming Apple Watch 8 is rumored to get, too, or if it's just a gimmick.

For now, we can only look at its potential. 

At first glance, skin temperature tracking may not seem as helpful as prior smartwatch additions like sleep tracking, ECG functions that watch for heart arrhythmias or blood oxygen monitoring for sleep apnea. It's not even clear what skin temperature changes actually signify. During Unpacked, Samsung vaguely hinted that they could indicate possible illnesses or other conditions.

Welcome to the feature-creep race among wearables, where manufacturers jam in a new capability in the hopes of proclaiming their product superior to the competition – and therefore the healthier option. With Apple having solidified a massive lead in smartwatches, companies like Samsung have to go the extra mile to convince you that their wearables are worth a second look. 

But compared to changes in heart rate or sleep, it's less obvious how skin temperature translates to health. Unlike core temperature, a variety of factors like outdoor heat, exercise, eating and menstrual cycles can affect skin temperature too, so wearables rely on other sensors to account for things happening outside your body to isolate the changes going on inside it.

To benefit from skin temperature monitoring, readings must be taken over time to establish a baseline, said Ramon Llamas, research director at analyst firm IDC. If you're normally trending at 96.9 degrees Fahrenheit and spike up to 99.1 for a prolonged period, you could be coming down with something. A smartwatch like the Galaxy Watch 5 could combine those skin temperature readings with heart rate, breathing, sleep tracking, blood oxygen levels and other metrics for a comprehensive report on your health.

"Now we have a clearer readout that can tell us if you are really sick or if it may be a passing thing," Llamas said.

The Galaxy Watch 5 isn't the first wearable to track skin temperature changes. The Oura Ring monitors skin temperature and reveals findings through its paired app, while the latest Fitbit Sense is a wrist wearable that shows temperature changes on its display. 

While Samsung has been coy about what other ways its watch could use skin temperature, it's invited app developers to innovate their own ways to harness the feature. But the company could learn from what other wearables have done with skin temperature tracking for years.

Oura got there first 

The Oura Ring wearable has had skin temperature tracking as a feature for years. It was initially included to augment sleep tracking, as dermal temperature shifts can show when users enter and exit different sleep stages, said Caroline Kryder, product marketing manager for Oura. Skin temperature is one of several metrics that feed into a "readiness score." If the score is lower than normal, you could potentially be ill.

"It flags to you, hey, your temperature looks higher than normal and your heart rate is higher than normal, these are common signs of strain and you may be coming down with something," Kryder said. 

Oura has developed new ways to analyze health data taken by the Ring wearable in the years since it launched. Early in the pandemic, researchers at the University of California San Francisco monitored Ring users to see if the finger-based wearables could detect COVID infections, publishing a paper in late 2020 showing potential to track COVID infections by watching skin temperature changes for fevers. NBA teams outfitted players with Oura rings for the same reason. 

Two years later, despite continued research, the wearables can't detect COVID outright. Instead, Kryder noted, users may see irregularities in health metrics like skin temperature, heart rate or blood oxygen ratings and then talk to their medical practitioner in case those portend a COVID infection. 

But other partnerships have brought new ways to use Oura Rings, including pairing it with the FDA-approved Natural Cycles app to determine daily fertility using the wearable to analyze skin temperature and other factors. 

It's these applications that pave the way for the Galaxy Watch 5.

Making progress on the COVID front 

Oura wasn't the only one looking to tackle COVID. Swarup Bhunia, professor and director of the Warren B. Nelms Institute for the Connected World at the University of Florida, worked with a team of academics in the development of an affordable wearable that measures skin temperature to predict COVID infection even when the wearer is asymptomatic. 

Bhunia and his team didn't try the wearable prototype out on people with COVID directly. Instead, they used data from several doctors on COVID patient skin temperature variations, outlined in a paper published in IEEE back in January, and built models to detect those variations in their wearable. 

"That was giving us confidence that [our wearable] can detect COVID for people who do not have observable symptoms," Bhunia said. 

Bhunia's team of researchers is seeking to turn its prototype into a production-ready wearable for public use. Unlike the Samsung Galaxy Watch 5, it'll be very cheap, just $10 or $15, to hand out to groups of people watching for COVID.

Nobody else is as close to making cheap COVID-detecting wearables, Bhunia said, noting that his design could start production as early as next year. By then, it could be used to track more than COVID. Patients could monitor the development of conditions like liver cirrhosis or diabetes by observing trends in skin temperature changes.

That's valuable insight, whether it comes from a cheap wearable for the masses or a pricey smartwatch. It makes sense why Samsung has added skin temperature tracking to the Watch 5 -- more sensors, more data.

"Combining [skin temperature] with the other sensors together can give a much more meaningful set of information to the health care professional, and even individually," Bhunia said.  

In the right hands, combining skin temperature with the array of data already collected by the Galaxy Watch 5 could ensure it's more than just a gimmick.