Nobre e Souza MÂ, Lima MJ, Martins GB, Nobre RA, Souza MH, de Oliveira RB, dos Santos AA. Inspiratory muscle training improves antireflux barrier in GERD patients. Am J Physiol Gastrointest Liver Physiol 305: G862-G867, 2013. First published October 10, 2013 doi:10.1152/ajpgi.00054.2013.-The crural diaphragm (CD) is an essential component of the esophagogastric junction (EGJ), and inspiratory exercises may modify its function. This study's goal is to verify if inspiratory muscle training (IMT) improves EGJ motility and gastroesophageal reflux (GER). Twelve GER disease [GERD; 7 males, 20 -47 yr, 9 esophagitis, and 3 nonerosive reflex disease (NERD)] and 7 healthy volunteers (3 males, 20 -41 yr) performed esophageal pH monitoring, manometry, and heart rate variability (HRV) studies. A 6-cm sleeve catheter measured average EGJ pressure during resting, peak inspiratory EGJ pressures during sinus arrhythmia maneuver (SAM) and inhalations under 17-, 35-, and 70-cmH2O loads (TH maneuvers), and along 1 h after a meal. GERD patients entered a 5-days-a-week IMT program. One author scored heartburn and regurgitation before and after IMT. IMT increased average EGJ pressure (19.7 Ϯ 2.4 vs. 29.5 Ϯ 2.1 mmHg; P Ͻ 0.001) and inspiratory EGJ pressure during SAM (89.6 Ϯ 7.6 vs. 125.6 Ϯ 13.3 mmHg; P ϭ 0.001) and during TH maneuvers. The EGJ-pressure gain across 35-and 70-cmH2O loads was lower for GERD volunteers. The number and cumulative duration of the transient lower esophageal sphincter relaxations decreased after IMT. Proximal progression of GER decreased after IMT but not the distal acid exposure. Low-frequency power increased after IMT and the higher its increment the lower the increment of supine acid exposure. IMT decreased heartburn and regurgitation scores. In conclusion, IMT improved EGJ pressure, reduced GER proximal progression, and reduced GERD symptoms. Some GERD patients have a CD failure, and IMT may prove beneficial as a GERD add-on treatment. crural diaphragm; GERD; lower esophageal sphincter; muscle training