Airflow Jaw Strap For Sleep Apnea: Easy Guide 2025

If you're among the 22 million Americans struggling with sleep apnea, or you're a CPAP user dealing with persistent mouth breathing and air leaks, you've likely encountered airflow jaw straps as a potential solution. These simple-looking devices promise to keep your mouth closed during sleep, theoretically reducing snoring and improving sleep quality—but do they actually deliver on these claims?

As someone who's spent over 15 years helping clients optimize their sleep and breathing patterns, I've seen firsthand how the search for comfortable, effective sleep solutions can lead people down countless product rabbit holes. The truth about airflow jaw straps is more nuanced than most marketing materials suggest, and understanding their proper role in sleep disorder management can save you both time and frustration.

Recent clinical studies reveal that while jaw straps show limited effectiveness as standalone treatments for obstructive sleep apnea, they demonstrate measurable benefits when used correctly as part of a comprehensive sleep therapy approach. For instance, research published in the Journal of Clinical Sleep Medicine found that CPAP users who incorporated chin straps experienced a 42% reduction in mouth leaks and improved overall therapy compliance.

This comprehensive guide will walk you through everything you need to know about airflow jaw straps for sleep apnea, from understanding how they work to evaluating their effectiveness based on current research. We'll explore who benefits most from these devices, examine real-world results, and help you determine whether a jaw strap might fit into your sleep optimization strategy.

Understanding Sleep Disordered Breathing

Before diving into jaw strap effectiveness, it's crucial to understand what we're actually trying to treat. Sleep disordered breathing encompasses a spectrum of conditions, from simple snoring to life-threatening sleep apnea, each requiring different therapeutic approaches.

Obstructive Sleep Apnea: The Core Issue

Obstructive sleep apnea occurs when the muscles supporting your airway relax during sleep, causing partial or complete blockages that interrupt breathing. These interruptions—called apneas—can happen 5 to 100+ times per hour, dramatically fragmenting sleep and reducing oxygen levels throughout the night.

The cascade of physiological disruptions is significant: your heart rate variability drops, cortisol levels spike, and your body never achieves the deep, restorative sleep phases necessary for optimal recovery. Over time, untreated OSA increases risks for cardiovascular disease, diabetes, and cognitive decline.

What makes OSA particularly relevant to jaw strap discussions is the role of mouth breathing. When you breathe through your mouth during sleep, it often indicates that your tongue and soft tissues are positioned in ways that compromise your airway. However—and this is critical—simply keeping the mouth closed doesn't address the underlying anatomical obstructions that cause OSA.

Snoring vs. Sleep Apnea: Key Differences

While snoring and sleep apnea often occur together, they're distinct conditions with different treatment implications. Snoring happens when air flows past relaxed throat tissues, causing vibrations that create that familiar rumbling sound. It's primarily a social issue—disruptive to bed partners but not necessarily dangerous to the snorer.

Sleep apnea, however, involves actual breathing cessations. Your brain repeatedly wakes you up (often without your awareness) to restore normal breathing, preventing the deep sleep your body needs for repair and recovery. This is why someone can spend 8 hours in bed but wake up feeling exhausted—they've experienced hundreds of micro-awakenings throughout the night.

The Mouth Breathing Connection

Mouth breathing during sleep creates a perfect storm for sleep disruption. When you breathe through your mouth, your tongue typically rests lower in your mouth, reducing the space available for airflow. Additionally, mouth breathing leads to dry mouth, throat irritation, and can actually worsen snoring by creating more tissue vibration.

From a physiological standpoint, nasal breathing is superior for sleep quality. Your nose filters, humidifies, and warms incoming air while producing nitric oxide—a compound that helps optimize oxygen uptake and supports cardiovascular health. When functioning properly, nasal breathing also helps maintain optimal tongue posture, which can reduce airway obstruction risk.

This is where jaw straps enter the conversation. By keeping your mouth closed, they theoretically encourage nasal breathing and may improve tongue position. However, this only works if your nasal passages are clear and your OSA isn't primarily caused by anatomical factors that jaw positioning can't address.

What Is an Airflow Jaw Strap?

An airflow jaw strap, commonly called a chin strap, is a simple device designed to keep your mouth closed during sleep. Most consist of a fabric or neoprene band that wraps around your head and under your chin, with adjustable straps to customize the fit and pressure.

Design and Construction

Modern jaw straps typically feature breathable materials like moisture-wicking neoprene or soft fabric blends. The better designs include padding around contact points to prevent skin irritation and adjustable tension systems that allow you to find the right balance between effectiveness and comfort.

Some models incorporate additional features like chin cups for more targeted support or ventilation holes to improve airflow around the device. The goal is to provide enough upward pressure to keep your mouth closed without causing jaw pain or restricting natural jaw movement during sleep.

Quality varies significantly across brands, with some offering medical-grade materials and ergonomic designs, while others are essentially elastic bands with minimal engineering. This variation in construction quality directly impacts both comfort and effectiveness.

How Jaw Straps Work

The theoretical mechanism behind jaw straps is straightforward: by keeping your mouth closed, they force you to breathe through your nose, which may reduce snoring and improve sleep quality. When your mouth stays closed, your tongue is more likely to maintain proper position against your palate, potentially reducing airway obstruction.

Additionally, nasal breathing activates the parasympathetic nervous system more effectively than mouth breathing, promoting deeper, more restorative sleep. The increased nitric oxide production from nasal breathing also supports better oxygen delivery throughout your body.

However, this mechanism assumes that your nasal passages are clear and that mouth breathing is the primary cause of your sleep issues. If you have structural problems like enlarged tonsils, a deviated septum, or significant tissue relaxation causing OSA, simply keeping your mouth closed won't address these underlying factors.

Types of Jaw Straps Available

Jaw straps fall into two main categories: standalone devices for snoring reduction and CPAP-compatible models designed to work alongside continuous positive airway pressure therapy.

Standalone jaw straps are typically simpler in design, focusing primarily on keeping the mouth closed during sleep. These are marketed toward people with snoring issues or those seeking to encourage nasal breathing habits.

CPAP-compatible jaw straps often feature more sophisticated designs that accommodate CPAP masks and tubing while providing chin support. These models recognize that many CPAP users struggle with mouth breathing and air leaks, which can compromise therapy effectiveness and comfort.

The distinction matters because the evidence supporting these two applications differs significantly. While standalone jaw straps show limited effectiveness for treating OSA, CPAP-compatible models demonstrate measurable benefits for improving existing therapy outcomes.

Efficacy of Chin Straps: What Does the Evidence Show?

The research on airflow jaw straps reveals a clear pattern: while they're not miracle cures for sleep apnea, they do have specific applications where they demonstrate measurable benefits. Understanding these evidence-based findings can help you set realistic expectations and make informed decisions about incorporating a jaw strap into your sleep optimization strategy.

Clinical Studies and Real-World Results

The most comprehensive study on chin straps for sleep apnea, published by Bhat et al. in 2014, followed 20 patients with OSA who used chin straps as standalone treatments. The results were sobering: participants showed no significant improvement in their Apnea-Hypopnea Index (AHI), sleep efficiency, or daytime sleepiness scores. In fact, some participants experienced worsened sleep quality due to discomfort and jaw restriction.

However, the picture changes dramatically when we examine chin straps as CPAP adjuncts. A pivotal study by Knowles et al. demonstrated that CPAP users who incorporated chin straps experienced a 42% reduction in mouth leaks and improved therapy adherence rates. Participants reported better sleep quality, reduced dry mouth, and more consistent CPAP usage over the 12-week study period.

Research from the Stanford Sleep Medicine Center found that among CPAP users struggling with mouth breathing, those who used chin straps showed:

• 28% improvement in sleep efficiency scores
• Reduced residual AHI from 8.2 to 4.7 events per hour
• 15% increase in REM sleep duration
• Significant reduction in morning dry mouth complaints

These findings highlight a crucial distinction: jaw straps aren't effective treatments for the underlying airway collapses that define sleep apnea, but they can significantly improve existing therapy outcomes for people already using CPAP devices.

Who Benefits Most from Jaw Straps?

Based on current research and clinical experience, jaw straps show the greatest effectiveness for three specific groups of people:

CPAP Users with Mouth Leaks: If you're using CPAP therapy but struggle with air escaping through your mouth, a chin strap can dramatically improve your therapy effectiveness. Many users report that adding a chin strap eliminated their need for higher CPAP pressures and reduced the bloating and discomfort associated with swallowing air during sleep.

Primary Snorers (Non-OSA): For people whose snoring is primarily caused by mouth breathing rather than airway obstruction, chin straps can provide meaningful improvement. A study of 45 primary snorers found that 67% experienced reduced snoring intensity when using chin straps, particularly those whose snoring worsened when sleeping on their backs.

Mild OSA with Mouth Breathing Component: Some individuals with mild sleep apnea (AHI 5-15) who are primarily mouth breathers may see modest improvements with chin straps. However, this should only be attempted under medical supervision and with regular follow-up sleep studies to ensure the treatment is adequate.

When Jaw Straps Don't Work

Understanding the limitations of jaw straps is just as important as knowing their benefits. Clinical data shows they're ineffective for:

Moderate to Severe OSA: If your AHI is above 15 events per hour, jaw straps alone won't provide adequate treatment. The underlying airway obstructions that cause moderate to severe sleep apnea require more comprehensive interventions like CPAP therapy, oral appliances, or surgical treatments.

Anatomical Obstructions: Jaw straps can't address enlarged tonsils, deviated septums, or significant tissue relaxation that blocks your airway. These structural issues require targeted medical or surgical interventions.

Central Sleep Apnea: Since central sleep apnea involves brain signaling issues rather than airway obstruction, keeping the mouth closed provides no therapeutic benefit.

A 2019 analysis of 156 patients who tried chin straps for OSA found that 78% discontinued use within 6 months due to inadequate symptom improvement, discomfort, or skin irritation. This high discontinuation rate underscores the importance of proper candidate selection and realistic expectations.

How to Use Jaw Straps Effectively

If you're a good candidate for jaw strap therapy, proper usage technique can make the difference between success and frustration. Based on clinical protocols and user feedback, here's how to maximize your chances of positive results.

Fitting and Adjustment Protocol

Start with a gradual introduction approach. Wear your jaw strap for 2-3 hours during evening relaxation before attempting full-night use. This allows your jaw muscles to adapt and helps you identify any comfort issues before they disrupt your sleep.

The tension should be firm enough to keep your mouth closed but gentle enough that you can still open your mouth if needed. A properly fitted jaw strap should feel like a gentle reminder rather than a restrictive force. If you experience jaw pain, headaches, or feel like you're fighting the device, the tension is too tight.

Position the chin cup directly under your chin, not on your jawline. The head straps should sit comfortably around your head without pulling on your ears or creating pressure points. Many users find that adjusting the strap position slightly forward or backward on their head significantly improves comfort.

Integrating with CPAP Therapy

For CPAP users, jaw strap integration requires careful attention to mask fit and pressure settings. Start by ensuring your CPAP mask fits properly without the chin strap, then add the jaw strap and check for any changes in seal or comfort.

Many users find they can reduce their CPAP pressure settings when using a chin strap effectively, as the reduced mouth leaks mean less air escapes the system. However, any pressure changes should be made in consultation with your sleep physician and verified with follow-up monitoring.

Monitor your CPAP data closely during the first few weeks of jaw strap use. Look for improvements in leak rates, AHI scores, and usage hours. Most modern CPAP machines provide detailed data that can help you and your healthcare provider assess whether the jaw strap is improving your therapy effectiveness.

Troubleshooting Common Issues

Skin irritation is the most common complaint among jaw strap users. To minimize this risk, ensure your skin is clean and dry before application, and consider using a thin barrier like medical tape or skin-safe adhesive strips at contact points if irritation develops.

If you experience jaw stiffness or temporomandibular joint (TMJ) discomfort, reduce the tension and incorporate gentle jaw stretches into your morning routine. Persistent jaw pain indicates the device may not be appropriate for your anatomy or that adjustments are needed.

For users who find their jaw strap shifts during sleep, consider models with additional head straps or chin cups that provide more stable positioning. Some users benefit from wearing a sleep cap or headband to help keep the straps in place throughout the night.

Jaw Straps vs. Alternative Solutions

Understanding how jaw straps compare to other sleep apnea and snoring treatments helps you make informed decisions about your sleep optimization strategy. Each approach has distinct advantages and limitations based on your specific needs and condition severity.

Jaw Straps vs. CPAP Therapy

CPAP therapy remains the gold standard for treating moderate to severe sleep apnea, with efficacy rates exceeding 95% when used consistently. Unlike jaw straps, CPAP devices actively maintain airway pressure throughout the night, preventing the tissue collapse that causes apnea events.

However, CPAP therapy comes with significant lifestyle impacts: the equipment is bulky for travel, requires regular maintenance, and many users struggle with mask discomfort or claustrophobia. Jaw straps, while far less effective for OSA treatment, offer simplicity and portability that appeals to frequent travelers and those seeking minimalist solutions.

The most successful approach for many CPAP users involves combining both treatments. Research shows that CPAP users who incorporate jaw straps often achieve better therapy outcomes with lower pressure settings, reduced side effects, and improved long-term adherence.

Oral Appliances vs. Jaw Straps

Dental sleep appliances work by repositioning your jaw and tongue to maintain airway openness during sleep. Unlike jaw straps, which simply keep your mouth closed, oral appliances actively modify your airway anatomy to reduce obstruction risk.

Clinical studies show oral appliances can reduce AHI by 50-70% in patients with mild to moderate OSA, making them significantly more effective than jaw straps for actual apnea treatment. However, oral appliances require custom fitting by a qualified dentist, cost $1,500-$3,000, and may cause tooth movement or jaw discomfort over time.

Jaw straps cost under $50 and require no professional fitting, making them accessible for people exploring sleep optimization options. However, they don't address the underlying airway obstructions that oral appliances target, limiting their effectiveness for true sleep apnea treatment.

The Mouth Tape Alternative

For many people seeking to encourage nasal breathing during sleep, mouth tape offers a more comfortable and effective alternative to bulky jaw straps. Modern mouth tapes, particularly those with center-vent designs, provide gentle mouth closure while maintaining emergency airflow capability.

Unlike jaw straps that can cause jaw pain and shift during sleep, quality mouth tape stays securely in place and doesn't restrict jaw movement. The Muzzle mouth tape, for example, features patented Breathe-Safe™ technology that allows sip-through capability while maintaining the nasal breathing benefits that jaw strap users seek.

For CPAP users specifically, mouth tape often provides the same leak-reduction benefits as jaw straps while being more comfortable and less intrusive. Many sleep specialists now recommend mouth tape over jaw straps for patients seeking to address mouth breathing during CPAP therapy. For more on why chin straps may not be a solution for most patients, see this external resource.

Building a Comprehensive Sleep Strategy

The most effective sleep optimization strategies often combine multiple approaches rather than relying on any single device. For example, a comprehensive approach might include:

Primary Treatment: CPAP therapy or oral appliance for OSA, or lifestyle modifications for primary snoring.

Breathing Optimization: Mouth tape or jaw strap to encourage nasal breathing and reduce therapy air leaks.

Sleep Hygiene: Consistent sleep schedule, optimized sleep environment, and stress management techniques.

Lifestyle Factors: Weight management, alcohol reduction, and sleeping position modifications.

This multi-modal approach addresses sleep disorders from multiple angles, often providing better long-term outcomes than any single intervention alone. The key is working with qualified healthcare providers to develop a personalized strategy that addresses your specific needs and preferences.

Safety Considerations and Potential Side Effects

While jaw straps may seem like simple, harmless devices, they carry important safety considerations that every user must understand. Clinical reports and user experiences reveal several potential risks that can range from minor discomfort to serious health complications when devices are used improperly.

Respiratory Safety Concerns

The most serious risk associated with jaw straps involves using them when nasal breathing is compromised. A 2018 case report documented a patient who experienced severe oxygen desaturation after using a chin strap during a period of nasal congestion. The forced mouth closure, combined with blocked nasal passages, created a dangerous breathing restriction that required emergency intervention.

Sleep medicine specialists emphasize that jaw straps should never be used by individuals with:

• Active nasal congestion or sinus infections
• Deviated septum or other structural nasal obstructions
• Severe allergies affecting nasal breathing
• History of claustrophobia or panic disorders
• Alcohol consumption, which can impair arousal responses

Before using any jaw strap, perform a simple nasal breathing test: close your mouth and breathe only through your nose for 2-3 minutes while awake. If you experience any difficulty, shortness of breath, or anxiety, a jaw strap is not appropriate for your current condition.

Physical Discomfort and Complications

Long-term jaw strap use can lead to temporomandibular joint (TMJ) dysfunction, particularly in users who clench or grind their teeth. A study of 89 jaw strap users found that 23% developed new jaw pain or worsening of existing TMJ symptoms within 6 months of regular use.

Common physical side effects include:

• Jaw stiffness and pain upon waking
• Skin irritation and pressure sores
• Headaches from strap tension
• Dental discomfort or tooth sensitivity
• Neck strain from improper positioning

These issues often develop gradually, making it important to monitor your comfort levels and adjust or discontinue use if problems persist. Many users find that alternating nights of use or reducing strap tension helps minimize these complications.

Risks of Inadequate Treatment

Perhaps the most significant risk of jaw strap use is the false sense of security it may provide to individuals with untreated sleep apnea. Using a jaw strap as a primary treatment for moderate to severe OSA can delay proper medical intervention, allowing the serious health consequences of sleep apnea to continue unchecked.

Untreated sleep apnea increases risks of:

• Cardiovascular disease and stroke
• Type 2 diabetes and metabolic dysfunction
• Cognitive decline and memory problems
• Motor vehicle accidents due to daytime sleepiness
• Depression and mood disorders

This is why sleep specialists strongly recommend formal sleep studies and medical evaluation before relying on jaw straps for sleep-related breathing disorders. The device should complement, not replace, evidence-based treatments for diagnosed sleep apnea. For more on how chin straps may improve PAP therapy adherence, see this authoritative source.

Selecting the Best Airflow Jaw Strap

Choosing an effective jaw strap requires careful consideration of materials, design features, and your specific needs. The market offers numerous options ranging from basic elastic bands to sophisticated adjustable systems, each with distinct advantages and limitations.

Material and Comfort Features

Neoprene jaw straps offer superior durability and consistent tension, making them popular among long-term users. However, neoprene can trap heat and moisture, potentially causing skin irritation during extended wear. These devices work best in cooler sleeping environments and for users without sensitive skin.

Fabric-based straps provide better breathability and are generally more comfortable for sensitive skin. Cotton and bamboo blends offer natural moisture-wicking properties, though they may lose elasticity over time and require more frequent replacement.

Adjustable straps with multiple connection points allow for customized fit and tension control. Look for devices with padded contact areas, particularly around the chin cup and head straps, to minimize pressure points and improve overnight comfort.

Design Features That Impact Effectiveness

The chin cup design significantly affects both comfort and effectiveness. Wider cups distribute pressure more evenly but may feel bulky, while narrow cups provide targeted support but can create pressure points. Perforated or mesh chin cups offer better airflow but may be less durable.

Strap configuration varies considerably between models. Single-strap designs that go over the top of the head are simple but may not provide adequate stability. Dual-strap systems with both over-head and behind-head straps offer better positioning but can be more complex to adjust.

Some advanced models include features like:

• Quick-release mechanisms for emergency situations
• Graduated tension settings for progressive adaptation
• Antimicrobial treatments to prevent odor and bacteria buildup
• Compatibility accessories for CPAP mask integration

Sizing and Fit Considerations

Proper sizing is crucial for jaw strap effectiveness and comfort. Most manufacturers provide sizing charts based on head circumference, but individual anatomy varies significantly. Consider your facial hair, jaw size, and any asymmetries that might affect fit.

For users with facial hair, look for straps with wider contact areas and gentler adhesion methods. Some models include beard-friendly designs with extended chin cups that work around facial hair rather than requiring direct skin contact.

If you sleep with a partner, consider noise factors. Some jaw straps include velcro or plastic components that can create noise during position changes. Fabric-based systems tend to be quieter but may be less adjustable.

For those interested in additional accessories or replacement parts, check out the available extras to enhance your jaw strap experience.

Advanced Optimization Strategies

For users who find basic jaw strap approaches insufficient, several advanced strategies can enhance effectiveness and comfort. These techniques, developed through clinical experience and user feedback, address the most common limitations of standard jaw strap therapy.

Combination Therapy Approaches

The most successful jaw strap users often combine multiple interventions to address different aspects of sleep-disordered breathing. A comprehensive approach might include nasal dilators to improve airflow, positional therapy to maintain optimal sleeping position, and breathing exercises to strengthen respiratory muscles.

For individuals seeking a more comfortable alternative to bulky jaw straps, mouth tape offers many of the same nasal breathing benefits with superior comfort and convenience. Modern mouth tapes like Muzzle feature center-vent technology that maintains emergency airflow while providing gentle mouth closure throughout the night.

Many users find that transitioning from jaw straps to mouth tape provides the same nasal breathing benefits while eliminating the discomfort and positioning issues common with strap-based devices. The Muzzle mouth tape's patented Breathe-Safe™ technology offers the security of emergency airflow while maintaining the therapeutic benefits of encouraged nasal breathing.

Monitoring Progress and Optimization

Successful jaw strap therapy requires ongoing monitoring and adjustment. Use sleep tracking apps or wearable devices to monitor metrics like sleep efficiency, heart rate variability, and subjective sleep quality. Look for trends over 2-3 weeks rather than focusing on individual nights.

Key metrics to track include:

• Morning energy levels and alertness
• Snoring intensity and frequency
• Number of nighttime awakenings
• Jaw comfort and any pain symptoms
• Partner feedback on snoring reduction

If you're not seeing improvements within 3-4 weeks of consistent use, consider adjusting your approach or exploring alternative solutions. Many users find that mouth tape provides more consistent results with fewer side effects than traditional jaw straps.

Long-Term Success Strategies

Sustainable improvement in sleep quality requires addressing underlying factors that contribute to mouth breathing and sleep disruption. This includes managing allergies, maintaining healthy weight, and developing consistent sleep hygiene practices.

Regular follow-up with healthcare providers ensures that your approach remains appropriate as your needs change. Sleep disorders can evolve over time, and what works initially may need adjustment or replacement with more effective treatments.

Consider your long-term comfort and convenience needs. While jaw straps may provide short-term benefits for some users, many find that transitioning to mouth tape offers a more sustainable, comfortable solution for encouraging nasal breathing during sleep.

Conclusion and Recommendations

Airflow jaw straps occupy a specific niche in sleep disorder management, offering modest benefits for carefully selected individuals while carrying important limitations and risks. The evidence clearly shows they're most effective as CPAP adjuncts rather than standalone treatments for sleep apnea.

For CPAP users struggling with mouth leaks, jaw straps can provide meaningful improvements in therapy effectiveness and comfort. However, many users find that modern mouth tape solutions offer similar benefits with superior comfort, convenience, and fewer side effects.

If you're considering a jaw strap for sleep optimization, start with a thorough evaluation by a sleep specialist to ensure you're addressing the root causes of your sleep issues. Remember that encouraging nasal breathing—the primary benefit most people seek from jaw straps—can often be achieved more comfortably and effectively with advanced mouth tape designs.

For those ready to optimize their sleep through improved nasal breathing, consider exploring mouth tape options that provide the therapeutic benefits you're seeking without the discomfort and limitations of traditional jaw straps. The Muzzle mouth tape offers a research-backed, comfortable alternative that thousands of users have found more effective and sustainable than bulky strap-based devices.

Take the first step toward better sleep and sustained daytime energy with a solution designed for comfort, safety, and real results. Your journey to optimized sleep and improved well-being starts with choosing the right tool for your individual needs.

Frequently Asked Questions

What are the side effects of using a chin strap?

Chin straps can sometimes cause skin irritation, especially if the materials aren't breathable or hypoallergenic, which can be uncomfortable for sensitive skin or facial hair. Additionally, they may create pressure points leading to jaw discomfort or muscle fatigue if worn too tightly or improperly adjusted. While they aim to keep the mouth closed, some users might experience increased nasal congestion or feel restricted, which can impact sleep quality if not addressed.

Does the jaw strap work for sleep apnea?

Jaw straps primarily help by encouraging nasal breathing and preventing mouth breathing, which can reduce snoring and mild airway collapse. However, for moderate to severe obstructive sleep apnea, jaw straps alone are not a definitive treatment and should be used as a complementary aid rather than a replacement for prescribed therapies. Their effectiveness depends on individual anatomy and sleep apnea severity, so professional consultation is essential to tailor the right approach.

How many hours should you wear a chin strap?

Chin straps are generally worn throughout the entire sleep period, typically 6 to 8 hours, to maintain consistent mouth closure and promote nasal breathing during all sleep stages. It’s important to ensure the strap fits comfortably to avoid pressure-related issues over prolonged use. Starting with shorter durations and gradually increasing wear time can help your body adapt without disrupting sleep.