Your Home Sleep Test Explained: A Guide to Understanding Your Sleep Health | Daybreak

A home sleep test is a convenient and affordable way to diagnose sleep apnea in the comfort of your own bed. Unlike traditional overnight sleep studies conducted in a sleep clinic or sleep center, a home sleep study allows you to take a sleep apnea test in the comfort of your own bed and on your own time.

Most home sleep studies use a small device worn on the chest, wrist, or finger to record sleep patterns. This type of sleep study, also known as an unattended sleep study, measures various bodily metrics, such as airflow, heart rate, peripheral arterial tone, and blood oxygen levels.

The home sleep test device is typically worn between one and two nights, but depending on the sleep data and device capabilities, more nights are not uncommon. More nights are often requested because there can be significant night-to-night variation in at-home sleep test results due to factors ranging from sleep position (notably supine or back-sleeping tends to encourage apnea events), the use of alcohol or other sedatives, stress, anxiety, the presence of a bed partner, and just general night-to-night randomness.

Because most home sleep studies are taken to identify and diagnose obstructive sleep apnea, these tests are also known as home sleep apnea tests. Depending on the test, it can detect sleep apnea and potentially other sleep-disordered breathing conditions, helping to provide a more comprehensive view of overall health.

Sleep apnea is a common sleep disorder that affects millions of people worldwide. It occurs when a person’s breathing is interrupted during sleep, causing them to stop breathing for short periods and depriving the body of oxygen.

These interruptions can be caused by a blockage in the airway, such as when the tongue or soft palate relaxes and obstructs airflow (known as Obstructive Sleep Apnea, or OSA), or by an intermittent absence of brain signals telling the body to breathe (known as Central Sleep Apnea, or CSA). Sleep apnea can lead to serious health consequences, including high blood pressure, heart disease, and stroke.

Common sleep apnea symptoms include loud snoring, daytime fatigue, morning headaches, excessive nighttime urination (nocturia), and restless sleep.

A home sleep test captures a range of measurements that reveal how well you sleep and whether sleep-disordered breathing is present. Key metrics in your personalized sleep report typically include:

• Sleep Efficiency: This is the percentage of time you spend asleep while in bed. Low sleep efficiency can signal fragmented sleep, which may result from sleep apnea or other conditions.
• Sleep Duration: The total amount of time spent asleep. Consistently short sleep duration can lead to chronic fatigue and long-term health risks.
• REM Time: The amount of time spent in rapid eye movement (REM) sleep, a critical phase for memory consolidation and emotional regulation. Disturbed REM sleep may indicate sleep apnea. Low REM sleep is an especially common indicator of sleep apnea in women.
• Apnea Events (Total): The total number of times breathing stops for at least 10 seconds. Frequent apnea events are a hallmark of obstructive sleep apnea (OSA).
• Unclassified Apnea Events (Total): These refer to breathing disruptions that don’t fit standard apnea classifications but still impact sleep quality.

The severity of sleep apnea is commonly assessed using the following indices:

• Apnea-Hypopnea Index (AHI): This measures the number of apnea events (breathing stops at least 10 seconds) and hypopnea events (shallow breathing) per hour of sleep. Almost all at-home sleep studies include at least one version of this measurement. Results are typically scored at two levels:
  • AHI at 3% Oxygen Desaturation: Includes events where oxygen levels drop by at least 3% relative to baseline. This is the more sensitive of the two AHI measurements and results in a higher AHI vs the AHI 4% measurement. It is also the preferred measurement for diagnosing sleep apnea by the American Academy of Sleep Medicine (AASM).
  • AHI at 4% Oxygen Desaturation: Includes events where oxygen levels drop by at least 4% relative to baseline. This is the less sensitive of the two AHI measurements and results in a lower AHI vs the AHI 3% measurement. The majority of health insurance companies require this clinical threshold to be met to approve coverage for any sleep apnea treatment, whether CPAP, surgery, or a sleep apnea mouthguard like the Daybreak Device. There are additional details and nuances around when health insurance pays for a sleep apnea oral device, but a 4% AHI clinical diagnosis is almost always table stakes.
• Respiratory Disturbance Index (RDI): Although similar to AHI, RDI includes additional breathing irregularities that disturb sleep without meeting apnea or hypopnea criteria. RDI is often higher than AHI, capturing a broader range of disruptions.

Obstructive sleep apnea (OSA) requires meeting specific criteria for diagnosis, commonly based on the Apnea-Hypopnea Index (AHI) described above. An AHI of at least five at the 3% level is the generally accepted minimum threshold for clinical sleep apnea diagnosis, with additional severity gradations defined below:

• Mild OSA: Mild obstructive sleep apnea is defined as an AHI of between 5 to 15 events per hour.
• Moderate OSA: Moderate obstructive sleep apnea is defined as an AHI of between 15 to 30 events per hour.
• Severe OSA: Severe obstructive sleep apnea is defined as an AHI of greater than 30 events per hour.

Understanding your OSA severity is critical for determining the appropriate treatment plan and prioritizing interventions to improve your health. Sleep apnea severity can also play an important role in sleep apnea insurance reimbursements.

Oxygen levels during sleep are crucial markers of health. Key metrics include:

• Oxygen Desaturation Index (ODI): The number of times oxygen saturation drops by a set percentage per hour.
• Lowest Desaturation (Minimum SpO2): The lowest recorded oxygen level during the test. Blood oxygen level drops are caused by both central sleep apnea and obstructive sleep apnea because, in either case, the body is temporarily prevented from breathing. Severe drops may signal critical health risks.
• Total Time Below Critical Thresholds: Time spent with oxygen saturation at or below specific levels (e.g., ≤ 90%, ≤ 85%). Prolonged low oxygen levels can stress the heart and brain.

Oxygen desaturation levels are monitored over one or more nights during the sleep study. Other metrics include maximum SpO2, average SpO2, and baseline SpO2, which provide a comprehensive view of your blood oxygen levels during sleep.

Heart rate variability during sleep offers insights into cardiovascular health. Metrics include:

• Minimum, Maximum, and Average Pulse: A wide range may indicate disrupted sleep or stress on the cardiovascular system. In particular, apnea events often trigger elevated heart rates as the cardiovascular system goes into overdrive in an attempt to compensate for lower blood oxygen levels.
• Ectopic Beats: Irregular heartbeats that might be linked to sleep-disordered breathing.
• Pulse Rate Percentages: The percentage of time your pulse exceeds 100 beats per minute (bpm) or falls below 60 bpm. These extremes can signal stress or poor oxygenation during sleep and are associated with sleep apnea.

If your HST results indicate sleep apnea, snoring, or other sleep-disordered breathing, seeking treatment can significantly improve your health and quality of life:

• Better Oxygen Levels: Treating sleep apnea restores healthy oxygenation, reducing strain on the heart and brain.
• Improved Sleep Quality: Addressing disruptions leads to deeper, more restorative sleep.
• Enhanced Daytime Energy: Quality sleep improves focus, mood, and productivity.
• Reduced Health Risks: Managing sleep apnea lowers the risk of hypertension, diabetes, and cardiovascular disease.

The most common sleep apnea treatments include CPAP therapy, various sleep surgeries, and sleep apnea mouthguards (also known as sleep apnea oral devices, also known as Mandibular Advancement Devices or MADs).

At Daybreak, we offer a fully at-home testing and treatment solution for individuals seeking a convenient and discreet way to address their sleep health. By providing accurate home sleep testing and an FDA-cleared oral appliance (the Daybreak Device), we make it simple to diagnose and treat sleep apnea and snoring. Daybreak allows you to enjoy the benefits of better sleep and overall wellness completely from the convenience of your own home.

Understanding your home sleep test results is the first step toward a healthier, more energized life. If you're ready to improve your sleep and address concerning results, take our sleep apnea assesment and start your journey to better health!

What does AHI mean?

The Anea-Hypopnea Index (or AHI) measures the number of apnea events on average per hour of sleep in which blood oxygen levels drop below an established baseline by either 3% or 4%.

What does RDI mean?

The Respiratory Disturbance Index (or RDI) includes additional breathing irregularities that disturb sleep without meeting AHI criteria.

What does REI mean?

The Respiratory Event Index (or REI) is a similar measurement to AHI but measures the average event per hour of device recording time rather than the hour of sleep. Consequently, it is often an underestimate of AHI and less commonly used for sleep apnea diagnostics.

What is Oxygen Desaturation?

Oxygen desaturation measures the extent to which blood oxygen levels decline, usually due to apnea events that pause or restrict breathing.

What metrics do insurance companies use to qualify claims?

Although every health insurance company is different, sleep apnea treatment is most commonly covered when AHI measured at a 4% level is greater than or equal to five. Other requirements, such as co-morbidities or failed treatments, may also be required depending on the health insurer, treatment, and diagnosed severity.

What qualifies as clinical sleep apnea?

The most commonly accepted diagnostic criteria, and the one advocated by the American Academy of Sleep Medicine (AASM), is an AHI of 5 or greater measured at the 3% level.

How do at-home sleep studies work?

Daybreak has put together a resource to learn about how at-home sleep testing works.