The most common form of sleep-related breathing disorder is Obstructive Sleep Apnea (OSA), which involves the repeated collapse of the upper airway during sleep. This collapse causes interruptions in breathing, leading to drops in blood oxygen levels and fragmented sleep. For many individuals, simple changes to their sleeping posture, known as positional therapy, can be a highly effective, non-invasive method for managing the condition by keeping the throat open.
The Impact of Gravity on Airflow
The physiological mechanism behind why certain positions worsen sleep apnea is directly related to gravity. When a person sleeps on their back (the supine position), gravity pulls the soft tissues of the mouth and throat backward. This displacement of the tongue and soft palate significantly narrows the pharyngeal space, making it susceptible to collapse.
This increased collapsibility raises the risk of breathing pauses and shallow breathing events (hypopneas). For up to 60% of people with OSA, the frequency of these respiratory events is higher when they are lying flat on their back. Shifting to a lateral, or side, position counteracts this gravitational pull, providing a wider and more stable airway structure.
Strategies for Side Sleeping
Adopting a side-sleeping position is the core goal of positional therapy, as it helps maintain airway patency by changing the direction of gravity’s force. To maximize the benefit, proper body alignment is important for comfort and long-term adherence. The head, neck, and spine should remain in a straight line, avoiding awkward angles that cause neck strain.
A thicker pillow is often recommended for side sleepers to fill the space between the head and the mattress, keeping the neck neutral. Placing a pillow between the knees helps align the hips and lower spine, reducing pressure points that might cause discomfort. Hugging a pillow to the chest also provides a physical barrier and helps the body settle into the lateral position.
While sleeping on either side is effective for OSA, some people prefer the left side for reasons related to digestion and acid reflux. The goal is establishing a comfortable lateral position and training the body to stay there throughout the night. Consistent use of these methods can significantly reduce the time spent in the supine position.
Positional Aids and Devices
For individuals who struggle to stay on their side using standard pillows, specialized aids and devices can provide additional compliance. Positional therapy belts or vests are worn around the chest or waist and contain a firm element or sensor that discourages back sleeping. Modern versions often use vibrotactile feedback, where a gentle vibration prompts the user to shift position without fully waking them up.
These devices are more comfortable and effective than historical methods like the “tennis ball trick,” where a ball was sewn into the back of pajamas. Another option is the use of specialized wedge pillows, which can be placed behind the back to prevent rolling or used to elevate the upper torso. This elevation helps reduce the effect of gravity on the upper airway, even when sleeping laterally.
Some positional aids are designed with cutouts to accommodate the mask and tubing for those who use Continuous Positive Airway Pressure (CPAP) therapy. These tools help maintain the side position, which can improve the comfort and effectiveness of the CPAP mask seal. Positional devices are particularly helpful for those with positional OSA, where most breathing disturbances occur only while supine.
When Positional Changes Are Not Enough
Positional therapy is an effective strategy, often comparable to other non-invasive treatments for mild-to-moderate Obstructive Sleep Apnea. However, it is not a universal cure and is typically most effective for patients whose condition is position-dependent. Those with severe OSA or non-positional apnea, where breathing disturbances occur equally regardless of posture, will likely require more intensive intervention.
The standard medical interventions for OSA involve devices that actively maintain airway patency. Continuous Positive Airway Pressure (CPAP) therapy remains the gold standard, using pressurized air delivered through a mask to mechanically splint the airway open. Oral Appliance Therapy (OAT) is another common treatment, using a custom-fitted mouthpiece to reposition the jaw and tongue forward. If positional changes do not resolve symptoms, consultation with a sleep specialist is the appropriate next step to explore comprehensive treatment options.