Diaphragm Fatigue Does Not Impact Breathing Mechanics or Function in People with Chronic Low Back Pain.

Abstract

Background and objective: The diaphragm is an important respiratory muscle that also plays a crucial role in developing intra-abdominal pressure and assisting in spinal stability. Chronic low back pain (CLBP) is a complex musculoskeletal condition and has been associated with respiratory problems and altered breathing mechanics. The purpose of this comparative cross-sectional study is to investigate whether diaphragm fatigue affects breathing mechanics and function in individuals with CLBP.

Methods: Volunteers were recruited between the ages of 35-65 years old with and without CLBP. Participants performed 30 minutes of exercises intended to fatigue the diaphragm. The following respiratory parameters were measured: Breathing mechanics (chest and abdominal movement and respiratory rate), diaphragm function (forced expiratory volume in 1 second (FEV1) using a handheld spirometer), and diaphragm movement as measured by sub-diaphragm (L1 to diaphragm domes) volume changes at the end of exhalation and inhalation using MRI scans.

Results: A total of 36 participants were recruited (n = 21M; n = 15F), with 18 participants suffering from CLBP (n = 10M; 8F) and 18 participants serving as a comparison group (n = 11M; n = 7F). There were no differences in breathing mechanics, diaphragm function or excursion (volumetrics) between people with and without CLBP after 30 minutes of exercises intended to fatigue the diaphragm.

Conclusion: The lack of differences suggests that the diaphragm, regardless of its fatigue status as a spinal stabilizer, will not relinquish or weaken its function as a breathing muscle, though it may be less effective as a spinal stabilizer. Individuals with chronic or recurrent low back pain might therefore be more susceptible to subsequent pain flare-ups than non-symptomatic individuals. A potential clinical implication of these findings is that incorporating diaphragmatic breathing exercises to enhance diaphragm function may offer an effective treatment option for patients with CLBP.