Obstructive Sleep Apnea (OSA) is a common condition where the airway repeatedly collapses during sleep. Gravity plays a significant role in this collapse, meaning that the position a person adopts while sleeping directly impacts the severity of these breathing events. For many individuals, simply changing how they sleep offers a non-invasive way to reduce the frequency of apneas. This positional therapy is effective for people whose condition is classified as positional OSA.
The Role of Body Position
The most impactful change an individual can make is shifting from sleeping on the back to sleeping on the side. The supine position, or back sleeping, is the least favorable posture for people with OSA because gravity pulls the tongue and soft palate backward. This causes the soft tissues to collapse into the throat, narrowing or obstructing the airway. Up to 60% of people with OSA experience a worsening of respiratory events when they are on their back.
Lateral sleeping, or side sleeping, is the preferred position as it minimizes this gravitational effect on the upper airway. When the body is on its side, the tongue and soft tissues are less likely to fall back, which helps maintain an open and clear breathing passage. This simple change can reduce the Apnea-Hypopnea Index (AHI)—a measure of breathing interruptions—by more than 50% for some individuals.
Some research suggests that sleeping specifically on the left side may be beneficial, not only for the airway but also for reducing symptoms of acid reflux. While either side is better than the back, the left-sided position can offer additional comfort and support better circulation. The prone position, or stomach sleeping, can also reduce airway collapse by pulling the soft tissues forward, but it is discouraged. This posture often causes strain on the neck and spine, which can lead to discomfort that disrupts sleep.
Aids and Techniques for Staying on Your Side
Maintaining a lateral sleeping position throughout the night often requires deliberate effort and training, as many people naturally revert to their backs. One of the oldest and simplest methods is the “tennis ball technique,” which involves sewing a tennis ball or similar object into the back of a pajama top. When the person rolls onto their back, the discomfort prompts them to shift back onto their side without fully waking up.
While the tennis ball method is low-cost, long-term compliance is often poor, leading to the development of more sophisticated positional training devices. These commercial solutions include specialized foam blocks, vests, or belts worn around the chest or waist. These physical barriers make sleeping on the back uncomfortable but not painful.
A more modern approach involves vibrotactile devices, which are small, electronic sensors worn on the chest or neck. These devices monitor the sleeping position and deliver a gentle vibration when the user rolls onto their back. The vibration is subtle enough to cause a positional change without interrupting the sleep cycle. These devices have shown better long-term adherence compared to older, purely mechanical methods. Strategically placed pillows can also serve as a positional aid, such as body pillows or wedge pillows placed behind the back to provide a physical block.
Incorporating Head and Torso Elevation
Integrating elevation for the head and torso offers mechanical assistance to keep the airway open, regardless of whether a person sleeps on their side or back. Elevating the upper body by 20 to 30 degrees (about 6 to 8 inches) reduces the gravitational pressure that causes soft tissue collapse. This semi-recumbent position, sometimes called Fowler’s position, can decrease the severity of breathing interruptions.
This elevation helps by slightly shifting the body’s center of gravity and preventing fluid accumulation in the neck tissues that can occur when lying flat. Using multiple pillows is not recommended, as this can flex the neck too sharply and strain the muscles, which can interfere with breathing.
The most effective ways to achieve this incline are with a foam wedge pillow that supports the entire torso or by physically raising the head of the bed frame on blocks or risers. Adjustable beds are the most convenient solution, allowing users to fine-tune the angle to find a position that is both comfortable and therapeutically effective. Studies have confirmed that a 30-degree head-of-bed elevation can lead to a reduction in upper airway collapse.
When Positional Changes Require Medical Intervention
Positional therapy, including side sleeping and elevation, is most effective for mild to moderate obstructive sleep apnea or for patients whose condition is classified as positional. For these individuals, breathing events occur predominantly when they are on their back. These non-invasive strategies may not be enough for people with severe OSA or those who experience breathing interruptions regardless of their body position.
When positional changes do not sufficiently reduce the frequency of apneas, a medical device is required. The standard treatment for moderate to severe OSA is Continuous Positive Airway Pressure (CPAP), which uses pressurized air to keep the airway open during sleep. An alternative is an oral appliance, a custom-fitted device worn in the mouth that gently shifts the jaw forward to prevent tissue collapse. It is important to consult with a sleep specialist to determine the severity of the condition and to establish whether positional therapy alone is an adequate and safe treatment option.