I asked Dr. Stern what that means...

With the popularity of wearable performance and sleep devices like Apple Watch, Google Fitbit, Whoop, Oura Ring and Withings ScanWatch, we get a lot of questions about what causes obstructive sleep apnea. By the end of this article, you should be able to comfortably say to your gym mates, “Yo, my SPO2 dropped below 90% last night. I can’t lift as much as I usually do, so I gotta boost those night-time oxygen levels.”

What are these devices trying to measure?

Quite simply...the amount of oxygen in your blood. The more, the better. You breathe in air through your lungs. Oxygen enters your bloodstream and moves through your body in red blood cells. The devices use a pulse oximeter, or a process called pulse oximetry, to measure your oxygen saturation levels - this is the amount of oxygen carried by the red blood cells. You're fully saturated if your red blood cells are carrying the maximum amount of oxygen. If you’re wicked technical, you’ll want to know that a multi-wavelength sensor called PPG (photoplethysmography) emits and measures red and infrared reflections in the blood vessels. What really matters is the percentage of oxygen carried by your blood cells.

How to measure obstructive sleep apnea (OSA)?

The over-the-counter devices have some limitations, so you need a Home Sleep Test to diagnose your Sleep Apnea. BlueSleep uses a 3-night home sleep test which you tape to your index finger. You might think you can bypass the test and jump to a CPAP or oral device, but insurance companies require a Home Sleep Test to pay for treatment. The test accurately measures pauses in your breathing and oxygen levels during the different stages of sleep over consecutive days. Based on your scores, you could have mild, moderate or severe sleep apnea.

Who cares about Sleep Apnea oxygen levels?

Your brain, for one. Normal oxygen levels are between 94% to 98%. If you stop breathing for 30 seconds or more during sleep, your 02 level could drop to 80% or less. In other words, your sleep apnea is causing...hypoxemia. Technically, if you’re taking shallow breaths for 10 seconds or longer while asleep, and your airflow drops below normal, you have a hypopnea. In any case, your noggin is not getting enough oxygen during sleep, and you might have a morning headache, excessive daytime sleepiness, and be gasping for air during sleep. None of these are good for you, not to mention your bed partner’s alarming elbow jabs and morning scowls from your snoring. If your sleep apnea goes untreated, a bad break up is the least of your worries. High blood pressure, weight gain, heart problems, among others, are likely to make life difficult.

So how come oxygen levels drop at night when you’re sleeping? During deep sleep and REM sleep, the throat can collapse, and air no longer gets to the lungs (apnea), or air has difficulty getting to the lungs (hypopnea). If this happens frequently (5 or more times an hour), it can cause damage to all the blood vessels in the body and repeated brain arousals (the brain wakes up), or awakenings (you wake up and can’t get back to sleep). That’s not good, because you lose out on necessary sleep.

What’s your action plan?

If your wearable device indicates low oxygen levels, or you’re snoring heavily and feeling sleepy all day, then do your health a favor and get tested for Sleep Apnea. A Home Sleep Test is easy and inexpensive, especially if you’ve got insurance. The next step is getting treated with a custom-made oral device (OAT) or a CPAP (if your sleep apnea is very severe). BlueSleep patients with severe apnea showed an 87% decrease in disease severity with an oral device. Sleep better. Live longer.

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