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

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.