The Musculoskeletal Consequences of Mouth Breathing in Adults: A Systematic Review.

OBJECTIVES

Although nasal breathing is the preferred pathway for quiet respiration, up to 30% of the population are habitual mouth breathers. This systematic review investigates the association between mouth breathing and musculoskeletal outcomes.

DATA SOURCES: A literature search was conducted on Medline, Embase, CINAHL, Web of Science, and Scopus from inception to August 8, 2025.

REVIEW

METHODS

Eligible studies included adults and investigated the association between chronic or induced mouth breathing (or relevant proxies such as nasal obstruction or induced nasal obstruction) and outcomes of musculoskeletal pain, temporomandibular joint dysfunction (TMD), changes in posture or muscle activity/electromyography (EMG). Outcome data were summarized using a narrative synthesis due to heterogeneity in included studies. GRADE was used to assess evidence certainty.

RESULTS

Studies evaluated the impact of chronic mouth breathing (n = 4) or induced mouth breathing (n = 8) on posture, TMD, masticatory muscle activity, and efficiency. No study evaluated the direct relationship between chronic or induced mouth breathing and pain. Compared to nasal breathers, mouth breathers had a higher prevalence of TMD, adopted a head forward posture and increased lumbar lordosis, demonstrated reduced chewing efficiency, and had reduced masseter and temporalis, and increased suprahyoid EMG activity. Certainty of evidence was very low.

CONCLUSIONS

This review found very low certainty evidence that chronic or induced mouth breathing may negatively impact posture, temporomandibular joint function, masticatory muscle activity, and efficiency. However, there is no data on whether there is an impact on pain. Due to the very low certainty of evidence, caution is recommended when interpreting the current literature.

LEVEL OF EVIDENCE: N/A.