After the release of Apple iWatch series 6 with watchOS 7, like many others I suddenly became curious about “blood oxygen” level and started doing some research to learn more about it. Because blood oxygen fuels our body for proper functioning, blood saturation is considered an overall indicator of wellness. According to the Cleveland Clinic Health Essentials, Doctors have discovered that some people with COVID-19 have dangerously low blood oxygen — even though they don’t feel short of breath.

According to the Mayo Clinic website, “Normal arterial oxygen is approximately 75 to 100 millimeters of mercury (mm Hg). Values under 60 mm Hg usually indicate the need for supplemental oxygen. Normal pulse oximeter readings usually range from 95 to 100 percent. Values under 90 percent are considered low.”

A Minnesota Department of Health document describes that “if a patient with COVID-19 has oxygen level, or saturation (SpO2) ≤90%, refer for further evaluation and possible treatment.”

Normal SpO2 is usually at least 95%. Some patients with chronic lung disease or sleep apnea can have normal levels around 90%. Medical professionals should be consulted if a patient with suspected or confirmed COVID-19 has SpO2 ≤90%. Supplemental oxygen or other treatments might be needed. If oxygen is available, it should be used for oxygen saturation levels <85%. Levels between 80–90%, and levels that are decreasing over time, often indicate severe disease and the potential for rapid decline.

Minnesota Department of Health

• Pulse Oximetry and COVID-19
• Should You Really Have a Pulse Oximeter at Home?
• Turns out I wasn’t dying of covid-19 after all. I was using my pulse oximeter the wrong way.

Pulse Oxymeter at Home

In a Washington Post article, Debra Bruno writes her perspective of how using a pulse oximeter incorrectly created anxiety in her family. In the article, Dr Sharon Chekijian, assistant professor of emergency medicine at Yale School of Medicine is quoted saying “if you are just checking and not feeling bad, and the number looks low, that’s probably not enough reason to be concerned”.

It can create so much anxiety. The right tool in the wrong hands can lead to a lot of anxiety.

Dr Sharon Chekijian, Emergency medicine doctor at Yale School of Medicine (source: The Washington Post)

Another pulmonary and critical care doctor at Johns Hopkins Hospital in Baltimore, Panagis Galiatsatos, is also quoted saying “while having a pulse oximeter at home is a useful device for patients with chronic obstructive pulmonary disease, or other lung disease, it could be misread by those who are not using it properly or don’t know how to interpret it in the context of their medical condition”.

iWatch and Blood Oxygen

Wayne Tsuang, MD, Cleveland Clinic Pulmonologist, says that though smart watches and fitness trackers measure blood oxygen saturation, their readings might not be as reliable as medical devices and should be used with caution. A healthy oxygen saturation is typically above 90% and if and when the number dips below 90%, then Dr Tsuang suggests one should consult his primary doctor.

“The low oxygen is just one sign of COVID-19. Even if you have a healthy blood oxygen level, don’t ignore other possible symptoms, like cough or shortness of breath,” cautions Dr Tsuang.

Let a medical expert — not your watch — create the action plan.

From the New York Times

The New York Times technology writer Brian X. Chen explains the new iWatch 6 “blood oxygen” features in a recent Times article and discusses Now what?, What to Know About Blood Oxygen Levels?, and why should I care? about blood oxygen level in our body.