Frequently Asked Questions

Yes — while the O2Ring doesn’t diagnose sleep apnea, it acts as a powerful screening tool.

It continuously tracks your oxygen saturation (SpO2) and pulse rate every second throughout the night. If you have sleep apnea, your breathing may pause repeatedly during sleep, causing oxygen levels to dip and heart rate to spike — and the O2Ring detects those patterns clearly.

- Oxygen drops below 90% can signal possible apnea events

- Heart rate spikes often follow breathing interruptions

- Real-time alerts and trend graphs make it easy to spot unusual patterns

It refers to the average blood oxygen saturation (SpO2) throughout the session. A healthy range is typically above 95%.

This is the average heart rate per minute during the session. Normal resting rates range between 60–100 bpm, though athletes and some users may have lower averages.

It detects physical movement during the session — useful to assess whether changes in oxygen or heart rate were linked to body movements.

02 Score is a measure of oxygen shortage during whole sleep. It combines frequency, duration, and depth of oxygen drops. A higher score means oxygen is richer; Lower score means oxygen is shorter. The score ranges from red (poor) to green (good).

For example, a score of 10 means no hypoxia.

Oxygen drops (or desaturation events) happen when your blood oxygen level falls temporarily — often during sleep or shallow breathing. While mild drops are normal, frequent or deep drops (especially below 90%) can signal issues like sleep apnea or lung problems.

Tracking them helps you spot early signs of breathing irregularities. In fact, the American Academy of Sleep Medicine (AASM) considers drops of ≥3% important for diagnosing sleep disorders, while Medicare uses a stricter ≥4% standard. Monitoring both ensures nothing gets missed.

These show how many times your oxygen level dropped by more than 4% from baseline, and how frequently this occurred per hour. 

The baseline refers to your average, stable oxygen level during a period of normal activity or rest, without significant fluctuations. For example, if your average oxygen level is 98%, a drop of more than 4% would mean your oxygen level drops below 94%.

The term “drops >4%” refers to oxygen level drops where your SpO₂ decreases by more than 4 percentage points—not 4% of a specific number. For example, if your oxygen level drops from 97% to 92%, that would count as a drop >4%. It’s an absolute difference, not a percentage of your original number.

This information is important for detecting breathing irregularities, such as sleep apnea, where oxygen levels can drop suddenly and repeatedly throughout the night. For instance, if your oxygen level drops below 94% multiple times per hour, it may indicate irregular breathing patterns that require attention.

Same as above, but for drops over 3%. Useful for detecting lighter but still significant fluctuations.

The American Academy of Sleep Medicine (AASM) is the leading professional society for sleep medicine in the U.S. It sets widely accepted clinical guidelines for diagnosing sleep disorders, including sleep apnea. AASM recommends scoring hypopneas when oxygen saturation drops by ≥3% or when there is an arousal from sleep.

The Centers for Medicare & Medicaid Services (CMS), known as Medicare, is the U.S. federal agency that manages health coverage for seniors and others. It uses a ≥4% oxygen drop criterion for scoring hypopneas when determining insurance coverage for sleep apnea treatment.

By tracking both thresholds, devices like O2Ring align with both medical and insurance standards — helping users and doctors make informed decisions without missing important signs.

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No, the number of 4% drops and 3% drops are not mutually exclusive. A 4% drop is a subset of 3% drops. This means if a drop qualifies as a 4% desaturation, it’s already included in the count of 3% drops. Therefore, you should not add the two together to calculate a total, as this would result in double-counting some events.

ODI stands for Oxygen Desaturation Index, which measures how many times your blood oxygen level drops by more than 3% and 4% during a specific period.

ODI 3% counts how many times your SpO₂ drops more than 3% from your baseline within a certain time period, typically per hour.

ODI 4% tracks how many times your SpO₂ drops more than 4% from the baseline during the same period.

The higher the ODI value, the more frequent the drops in oxygen levels, which may suggest potential issues that could require medical attention.

This shows the lowest and highest oxygen saturation recorded during the session.

This is the full range of your heart rate throughout the session.

It breaks down the time you spent in different oxygen level ranges:

95%–100%: Normal

90%–94%: Slightly low

<90%: Concerning — prolonged time here may signal a health issue.

This indicates how long your heart rate stayed in each range. A high percentage below 50 bpm during sleep can be normal for some, but if paired with symptoms, consult a doctor.

Use the “Add notes” section at the bottom of the report to log relevant symptoms or behaviors (e.g., coughing, CPAP usage).

PI" stands for Perfusion Index — a number that reflects the strength of blood flow at the sensor site (like your finger). It’s calculated from the pulse signal and is usually expressed as a percentage.

A higher PI means stronger blood flow, which can indicate better signal quality. Most people see values between 0.2% and 20%, depending on factors like temperature, movement, or circulation.

Why it matters:

- Low PI? Cold fingers, poor circulation, or loose fit might be affecting your signal. Try warming your hand or adjusting the ring.

- High PI? Good blood flow — your readings are more reliable.

- During sleep: Tracking PI changes may help you notice circulation issues or movement disturbances overnight.

Example: If your SpO₂ graph looks unstable or the app can’t detect your pulse, check the PI value — a low PI (<0.5%) often explains weak signals.

Please be assured that all Wellue products provide medically accurately measurement.

Different manufacturers utilize algorithms with different average SpO2 times, which is a significant element when calculating the reading. The shorter the collecting duration, the more sensitive the result, the fast the response. Oxygen monitor with too long assessment time is not the best choice for oxygen saturation detection, especially during sleep. Wellue’s intelligent averaging algorithm collects data quickly and identifies the precise SpO2 value. 

Therefore, it is not rigorous to compare oxygen monitors that utilize different averaging algorithms.The comparing result will be much more accurate if obtained by an arterial blood gas.

It’s normal to see a small difference—typically 2% to 5%—between the O2Ring and other oximeters, especially hospital fingertip models. That’s because:

- Different measurement positions: The O2Ring measures oxygen at the base or middle of your finger, while fingertip devices read at the tip. Blood flow and tissue thickness vary in each location.

- Different sensor technology and algorithms: Medical offices may use devices calibrated differently. The O2Ring is designed for continuous, overnight monitoring and uses proprietary algorithms to filter movement and noise.

- Circulation and temperature: Cold fingers, loose placement, or poor circulation can affect any pulse oximeter’s accuracy.

No manual calibration needed: The O2Ring is pre-calibrated. It does not support offset adjustments, but it reliably tracks real-time oxygen trends.

For best results, wear the ring snugly, keep your hands warm, and stay still during readings. While the O2Ring is excellent for daily monitoring and sleep tracking, always consult your physician for clinical diagnosis.