How Sleep Tests Reveal Causes of Poor Sleep Quality

If you wake up tired despite a full night in bed, you’re not alone.

Millions of adults struggle with poor sleep quality—snoring, frequent wake-ups, restless legs, or daytime fog—without knowing the underlying cause. Sleep tests can shine a light on what’s happening overnight and guide you toward the right equipment and lifestyle adjustments for deeper, more restorative rest.

What are sleep tests?

Sleep tests are assessments that monitor your breathing, oxygen levels, heart rate, movement, and other signals while you sleep. They help identify patterns—like pauses in breathing, frequent arousals, or leg movements—that may be disrupting your rest, even if you don’t fully wake up to notice them.

These tests don’t replace a clinician’s evaluation, but they provide objective data to help a qualified professional tailor next steps. Depending on your symptoms, a provider may recommend an in-lab sleep study or an at-home sleep test to capture the right information.

Primary care clinicians, dentists trained in sleep, and board-certified sleep specialists commonly order sleep testing. Many people start with a simple screening questionnaire and then move to testing if symptoms or risks are present.

In-lab sleep studies vs. at-home sleep tests

Both options can be effective—the best choice depends on your symptoms, overall health, and what your clinician needs to measure.

In-lab polysomnography (PSG)

An overnight, attended study in a sleep center records brain waves, eye movements, chin and leg muscle activity, heart rhythm, breathing effort and airflow, snoring, and oxygen saturation. This comprehensive setup helps evaluate complex sleep issues beyond breathing, including movement disorders and sleep architecture (how much light, deep, and REM sleep you get). Learn more about polysomnography.

PSG is often recommended if you have multiple health conditions, suspected narcolepsy or parasomnias, significant lung or heart disease, or if a prior at-home test was inconclusive.

At-home sleep apnea testing (HSAT)

HSAT devices are typically small kits you wear overnight at home. They primarily measure airflow, breathing effort, oxygen levels, heart rate, and snoring to detect obstructive sleep apnea. They’re convenient, less expensive, and reflect your typical sleep environment. See an overview of home sleep apnea testing.

HSAT is best for adults with a moderate-to-high likelihood of obstructive sleep apnea and no major complicating conditions. Because HSAT doesn’t track brain waves, it cannot diagnose certain non-breathing sleep disorders or precisely measure total sleep time; results sometimes need confirmation or follow-up with in-lab testing.

Who may benefit from sleep testing?

Adults or seniors who wake unrefreshed despite 7–9 hours in bed
Partners who notice loud snoring, choking, or pauses in breathing
People with morning headaches, dry mouth, or frequent nighttime urination
Those with daytime sleepiness, low energy, or trouble focusing
Individuals who toss and turn, or have restless or jerking legs at night
People who wake frequently and struggle to fall back asleep
Anyone with high blood pressure, atrial fibrillation, type 2 diabetes, or weight gain that worsens sleep symptoms
Drivers, shift workers, and safety-sensitive professionals who need reliable alertness

Sleep problems are common; about one in three U.S. adults doesn’t get enough sleep, and many are unaware of treatable causes. The CDC’s sleep basics offer a helpful overview of healthy sleep.

What sleep tests can uncover

Snoring: Testing can determine whether snoring is simply noisy airflow or a sign of airway narrowing that leads to repeated arousals or oxygen dips.

Obstructive sleep apnea (OSA): Sleep tests can reveal apnea (pauses) and hypopnea (shallow breaths) events and how often they occur. You might see an Apnea–Hypopnea Index (AHI) on your report, which quantifies events per hour.

Restless or fragmented sleep: In-lab studies can capture periodic limb movements and frequent arousals that fragment sleep quality, even if total time in bed looks adequate.

Difficulty staying asleep: Testing can show whether awakenings correlate with breathing events, environmental factors, or spontaneous arousals, which helps guide next steps like behavioral strategies or medical evaluation.

Daytime sleepiness: When sleep feels unrefreshing, objective data can clarify whether the issue is sleep quantity, sleep fragmentation, or an undiagnosed condition such as sleep apnea.

From results to next steps: equipment and lifestyle tools

Snoring and mild obstructive sleep apnea

Positional strategies: Sleeping on your side, elevating the head of the bed, or using a positional aid can reduce airway collapse for some people.
Nasal support: Treating nasal congestion, trying nasal dilator strips, or using a saline rinse may improve airflow.
Oral appliance therapy: A custom device fitted by a qualified dentist can advance the lower jaw to open the airway; often considered for primary snoring or mild-to-moderate OSA.
Lifestyle adjustments: Gentle weight management if appropriate, limiting alcohol near bedtime, and consistent sleep schedules can meaningfully improve symptoms.

Moderate to severe obstructive sleep apnea

PAP therapy (CPAP/APAP): A bedside device delivers air pressure through a mask to keep your airway open. Success hinges on fit and comfort—try different masks (nasal, pillow, or full-face) and use heated humidification if dryness occurs.
Comfort and adherence tips: Start with short daytime “mask acclimation” sessions, adjust straps to prevent leaks without over-tightening, and work with your provider to fine-tune pressures.
Follow-up matters: Reviewing device data (usage hours, leak, residual AHI) with your clinician helps optimize therapy and comfort over time.

Restless sleep and periodic limb movements

Discuss iron status: Low iron stores can contribute to restless legs; your clinician can advise on appropriate testing and treatment if indicated.
Evening habits: Limiting caffeine, nicotine, and heavy exercise close to bedtime; adding gentle stretching or a warm bath to your wind-down routine may help.
Comfort-focused tools: Supportive mattresses or breathable bedding can reduce tossing and turning; some people find light, evenly distributed blankets calming.

Difficulty staying asleep (maintenance insomnia)

CBT-I: Cognitive Behavioral Therapy for Insomnia is a structured, skills-based approach that helps retrain your sleep system and is considered first-line for chronic insomnia by many professional groups.
Sleep-friendly routines: Keep a consistent wake time, dim lights and screens in the evening, keep the bedroom cool, and limit late alcohol which fragments sleep.
Wind-down rituals: Journaling, light reading, or breathing exercises help cue your nervous system for rest.

Daytime fatigue despite “normal” results

Check the basics: Aim for 7–9 hours in bed, aligned with your natural chronotype; consider morning daylight exposure and movement breaks.
Medication and health review: Some prescriptions, pain, mood conditions, or thyroid issues can affect sleep quality—coordinate with your healthcare team.
Consider further evaluation: If sleepiness persists, a sleep specialist may recommend additional testing or targeted therapies.

How to get started with a sleep test

Track your sleep and symptoms for 1–2 weeks: bedtime/wake time, snoring, awakenings, morning headaches, or daytime dips.
Talk with a qualified professional: Start with your primary care clinician or a board-certified sleep specialist; dentists trained in sleep may help with oral appliance options.
Choose the right test together: In-lab PSG for complex concerns; HSAT for straightforward suspected OSA.
Check coverage and logistics: Many insurance plans cover testing when medically appropriate; your clinician’s office can help with authorizations.
Prepare for testing: Follow instructions about medications, avoid heavy caffeine/alcohol late in the day, wash your face and avoid heavy lotions so sensors adhere, and bring comfortable sleepwear.
Understand your report: Common terms include AHI (events/hour), oxygen nadir (lowest oxygen level), ODI (oxygen desaturation index), and arousal index. Typical AHI ranges used for OSA severity are mild (5–14), moderate (15–29), and severe (30+). Your clinician will interpret these in context.
Build your plan: Pair any recommended equipment with behavioral strategies (sleep schedule, light, movement, nutrition). Follow up to review progress and adjust.

The bottom line

Sleep tests offer a clear window into what’s disrupting your nights so you can take targeted action. With the right guidance, equipment, and daily habits, better sleep—and better days—are within reach. If you suspect a sleep disorder or your symptoms persist, consult a qualified professional to personalize your approach.