Background and Aim: Some of the patients with chronic low back pain commonly do not experience full recovery with the conventional physical therapy. It is revealed that may be there are some items in subjects with low back, which are not studied well till now. Since there are some evidences about breathing pattern disorder in low back pain patients, the purpose of this study was to compare between some important breathing pattern index in non-specific chronic low back pain and healthy subjects .

Materials and Methods : In this descriptive analysis study, there were 16 patients with chronic non-specific low back pain and 16 healthy subjects. Both groups were matched and selected by some of the demographic characteristics. Respiratory data including respiratory rate, volumetric, time depended and chemical index were calculated by K4b2 instrument.

Results: They have significant differences in some of the respiratory parameters including respiratory rate, inspiration and expiration times and total time of respiration between two groups, whereas inspiration total time ratio, volumetric and chemical index do not have significant differences.

Conclusion: Existence of disorders in some parameters of respiratory patterns in patients with low back pain are revealed that survey of respiratory system in patients with chronic non-specific low back pain can be effective in diagnosis and treatment process in physiotherapy centers.

Keywords: Low back pain, Breathing, Respiratory chemistry.