Lung Volume and OSA as Relates to Sleep Apnea Machines

Lung Volume and OSA as Relates to Sleep Apnea Machines

In recent years, researchers have been studying the correlation between lung volume, OSA and CPAP therapy. While CPAP therapy seems by most accounts to play a positive role in lung volume, just how much and in what specific ways is still in question.

While Obstructive Sleep Apnea (OSA) is associated with airway collapse due to throat muscle relaxation during sleep, the last few years have seen greater focus on the correlation between OSA, lung volume and CPAP therapy. Researchers acknowledge that the relationship between low lung volume and OSA is a complex one that will require further study. However, it behooves engaged OSA patients to understand some of the basics as evidence is showing that the positive effects of a sleep apnea machine also includes positive implications for maximizing lung volume.

In general terms, lung volume refers to the air holding capacity of the lungs. There are actually a variety of lung volume measurements as capacity varies depending on a number of factors ranging from body position and altitude to weight and height. Each of these lung volumes has a specific term but, in general, every person experiences a decrease in lung volume when they are prone or sitting verses when they are standing. This is regardless of general health and OSA.

There are studies that show increasing lung volume can reduce airway collapse in healthy non-obese individuals during sleep. Additionally, the same studies show that maximized lung volume lowers the air pressure level necessary to stop diminished air intake in OSA patients. Further, these studies show a significant correlation among obesity, dynamic lung volume and OSA severity. This result suggests that changes in dynamic lung volume may play an important role in the pathogenesis of OSA in obese patients.

There are numerous studies investigating the effect of body mass index (BMI) on respiratory function and lung volumes. Total lung capacity and residual volume (volume of air that is not expelled on exhalation) are only slightly affected in obese patients. Many of these studies show that the functional reserve capacity and other lung volume indicators for capacity reduce proportionally to higher BMI.

Currently however, there are few if any studies that look specifically at lung volumes in each of the various groups. This includes looking at non-obese patients with and without OSA exclusively or studies that look at obese patients with and without OSA exclusively.

Still, other studies that looked at the effects of manipulating lung volume via various means also looked at the effects of CPAP therapy via a CPAP machine.  Although the studies showed that increasing lung volume decreased the need for a CPAP machine, the various methods used to manipulate lung volume are impractical in normal sleep settings.

According to the study in question, researchers hypothesized that CPAP and proper use of a sleep apnea machine acts as a pneumatic “splint,” that prevents upper airway collapse while also increasing lung volume. However, researchers concluded that more studies must be done regarding the efficacy of the effect on increased lung volume while using a CPAP machine.

In fact, these findings remain controversial and in opposition to other studies. What all researchers seem to agree on is that lung volume plays an important role in upper airway collapsibility in OSA patients. That role will likely have a direct impact on how CPAP therapy works in conjunction with lung volume to provide relief for millions of people.

For additional information on various topics concerning sleep apnea and CPAP products, please refer to our blog.  It has updates constantly and offers free advice and information.  If you’d like to learn more about the quality sleep apnea products we carry, or if you have additional questions, don’t hesitate to call us at (866) 414-9700, or you can contact us through our website.

Chris Vasta CPAP Expert & President at The CPAP Shop


Chris Vasta

Over a 10+ year career at PHH Mortgage managing a $100 million portfolio, Chris Vasta learned the ins and outs of the business world. He learned how to establish business relationships, lead a multi-prong team, and implement strategies for long-term growth. In 2007, Vasta used that experience to transition his role into president of The CPAP Shop. Over his tenure, Vasta has been involved in everything from website design to warehouse layout. His hands-on approach with customers has evolved into an in-depth understanding of the challenges of beginning and adhering to sleep therapy. He often provides his insights on product…