Smartwatches have been measuring blood oxygen for years. But is this useful?

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Smart watch You can measure everything from heart rate to sleep quality, but over the last two years, one health indicator, blood oxygen saturation, has become particularly important. Two of the world’s largest smartwatch makers, Apple When Samsung, Added blood oxygen monitoring to wearables in 2020. The COVID-19 pandemic has also made vital measurements from home more desirable.

However, the advent of blood oxygen monitoring in smartwatches has also raised questions about how useful this information is without the context of medical professionals. CNET Apple Watch Series 6 Review, Vanessa Hand Orellana said he hopes the Apple Watch can provide more guidance associated with blood oxygen readings. (She didn’t know if she needed to worry when her level dropped to 92% overnight.) Most smartwatches are also approved by the US Food and Drug Administration for blood oxygen measurements. It has not been used and cannot be used for medical purposes. It is difficult to understand how these indicators should be interpreted.

After about two years, are blood oxygen readings more useful than in 2020? The answer is not that simple. According to medical experts, measuring blood oxygen under a variety of conditions throughout the day may provide insights not available with traditional pulse oximeters. In addition, making health data accessible from home is usually a good thing.

However, these sensors still have drawbacks that may limit their usefulness. And smartwatch makers are still looking for the best way to incorporate blood oxygen readings into a wide range of features that provide users with a complete picture of their overall health.

“We know that the science behind them isn’t as accurate as hospital-grade ones when it comes to measuring oxygen,” said Dr. Albert Rizzo, Chief Health Officer of the American Lung Association. rice field. “But that said, it’s now possible to track different vital signs from the patient’s point of view, or even medically ill or even healthy.”

A breakthrough in blood oxygen monitoring


Apple Watch Series 6 was the company’s first app to measure blood oxygen levels.

Screenshots by Sarah Mitroff / CNET

To understand whether measuring blood oxygen levels from a smartwatch is useful, it is important to first know what this metric means and how it is implemented in today’s wearables.your Blood oxygen concentration, Also called SpO2, refers to the amount of oxygen carried by red blood cells. It is considered an important indicator of respiratory health as it shows how much oxygen your body can absorb.

Blood oxygen saturation is usually Pulse oximeter It clips on your finger. Smartwatches like the Apple Watch measure this by shining light from your wrist and measuring the reflected light.

If you can’t measure your blood oxygen levels with your current smartwatch or fitness tracker, you may buy it next. This technology has become a staple of today’s wearables from Apple, Samsung, FitbitGarmin and Withings etc.

The Apple Watch Series 6 When Series 7 Similar to Samsung Galaxy Watch 3, both measure blood oxygen levels Watch 4.. Fitbit devices such as the Sense, Ionic, Versa smartwatch and Charge 4, Charge 5, and Luxe fitness bands can also measure blood oxygen levels overnight during sleep.

However, most companies are not FDA-approved for blood oxygen measurement technology. Withings is an exception. With ScanWatch Blood Oxygen Monitor ScanWatch Horizon both FDA approval.. Maxime Dumont, Product Manager for Withings smartwatches, said the FDA approval should make the data more reliable for physicians.

“We never replace doctors, and we are not intended to make a diagnosis with a watch,” he said. “But the clock results are reliable for doctors.”

read more: Fitbit and Apple know that smartwatches aren’t medical devices. but, you are?

It was possible to get blood oxygen readings from smartwatches before 2020, but this technology reached a breakout moment two years ago. As pandemics overwhelm hospitals and healthcare systems, there is growing interest in studying how wearables can monitor physical changes at home.

Apple, Fitbit, Garmin, and Oura devices are all used in studies to see if wearable devices can predict illness early by measuring changes in body signals such as heart rate and temperature. A 2021 study from researchers at the University of Sao Paulo and Centro Universitário FM ABC also found that the Apple Watch Series 6 is reliable in collecting SpO2 and heart rate data for patients with lung disease in a controlled environment. I understand.

Dr. Naumann Mustak, Dean of the Department of Cardiology at Northwestern Medicine Central Dupage, said: Derner Hospital.

How useful are these sensors in your smartwatch?

Withings ScanWatch Horizon

Withings ScanWatch Horizon is FDA approved for blood oxygen monitoring.

Lisa Eadicicco / CNET

Although smartwatch health sensors are promising in research, some experts may not know how often these sensors are used in everyday situations. Dr. Ashraf Fauzy, a pulmonologist, emergency physician and assistant professor of medicine at Johns Hopkins University, said: “But it wasn’t as common as I thought.”

Regarding regular use, Dr. Mushtaq, Apple watch Most useful for adding context regarding overall health. In most cases, the average healthy person will experience signs of physical warning before experiencing hypoxemia or hypoxemia, he said.

“Honestly, I don’t think I’m doing anything clinically meaningful to the average person,” he said.

That doesn’t mean that healthcare professionals don’t see the potential. Smartwatches have significant advantages over traditional pulse oximeters. It means that you can wear it on your wrist all day long. Many smartwatches can not only provide a spot check, but also make a back ground blood oxygen measurement. This means that you can collect data at different times of the day.

read more: Apple Watch Series 8 Rumors: More Health Features, New Rugged Version

Fitbit, Samsung, Garmin Apple devices can also passively monitor blood oxygen levels during sleep, unlike traditional pulse oximeters used for on-demand measurements. Both Apple and Garmin can sample blood oxygen levels on a regular basis throughout the day.

However, smartwatches are only good at checking SpO2 levels at rest, even when scanning in the background. (Apple says background measurements are taken when the wearer isn’t moving, and Garmin says it reads less often if it detects high movements).

According to Dr. Forsy, measuring blood oxygen levels during strenuous activity makes these devices more convenient because it helps doctors know whether to adjust the amount of oxygen prescribed to the patient. Probably. Dr. Mushtaq also said that patients with heart failure or pulmonary hypertension may benefit from seeing if blood oxygen levels decrease during exercise.

“It will certainly help,” said Dr. Forsy. “For some people, their oxygen levels will drop only when they are active and will be normal when they are sitting quietly.”

Health indicators, whether blood oxygen levels or steps, are most useful depending on the situation. Numbers and charts are important only if you know how to make good use of them.

“Ultimately, consumers aren’t buying sensors,” Julie Ask, vice president and principal analyst at research firm Forester, said in a previous interview with CNET. “They aren’t buying data. Consumers are buying what they want to help achieve results.”

Galaxy Watch-4-sleep-spo2

Samsung’s Galaxy Watch 4 measures blood oxygen levels overnight.

Scott Stein / CNET

So what context does a smartwatch need to provide to make blood oxygen saturation measurements more useful? Some companies are trying to answer that question by incorporating SpO2 results into other features and in-app wellness reports to better understand their overall health.For example, Samsung has SpO2 measurements Sleep guidance According to Samsung representatives, the features of Galaxy Watch 4 will help you understand your sleep patterns. Withings uses blood oxygen levels as one of the indicators to analyze when determining respiratory problems, along with heart rate and movement.

Phil McClendon, manager of Garmin’s wellness product management team, was unable to comment on future plans when asked if SpO2 measurements would be considered for other health insights. But he pointed out Garmin’s health snapshot as an example of the company’s approach to making health data more meaningful.

read more: How WatchOS 9 paves the way for the future of the Apple Watch

Health snapshots compile various metrics (heart rate, blood oxygen, heart rate variability, respiration, stress, etc.) to provide a high level view of cardiovascular status. According to McClendon, this feature helps quantify changes that can occur in the body during anomalous events.

“So they may have a panic attack, and they” I want to record this and export a PDF to take to my healthcare provider, “he said. Said as.

Currently, the biggest advantage of measuring blood oxygen levels from a smartwatch is learning what is considered normal to the body. A smartwatch isn’t meant for medical diagnostics, but it’s another signal that you can tell your doctor if you feel sick or notice a change in your body.

“Whatever device you’re using, compare it to the baseline and use it as a trend monitor to make sure it’s off the baseline,” said Dr. Rizzo of the American Lung Association. .. “It may allow you to change what you are doing or ask for help faster than any other way.”

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