Background and Aims High-resolution manometry (HRM) is used to measure anal pressures in clinical practice but normal values have not been available. While rectal evacuation is assessed by the rectoanal gradient during simulated evacuation, there is substantial overlap between healthy people and defecatory disorders, and the effects of age are unknown. We evaluated the effects of age on anorectal pressures and rectal balloon expulsion in healthy women. Design Anorectal pressures (HRM), rectal sensation, and balloon expulsion time (BET) were evaluated in 62 asymptomatic women ranging in age from 21 to 80 years (median age 44 years) without risk factors for anorectal trauma. Thirty women were aged less than 50 years. Results Age is associated with lower (r = − 0.47, p < 0.01) anal resting [63[5] (≥50 y), 88[3] (<50 y)] but not squeeze pressures; higher rectal pressure and rectoanal gradient during simulated evacuation (r = 0.3, p < 0.05); and a shorter (r = −0.4, p < 0.01) rectal BET [17[9]s (≥50 y) vs 31[10]s (<50 y)]. Only 5 women had a prolonged (> 60 s) rectal BET but 52 had higher anal than rectal pressures (ie, negative gradient) during simulated evacuation. The gradient was more negative in younger (−41[6] mm Hg) than older (−12[6] mm Hg) women and negatively (r = −0.51, p <0.0001) correlated with rectal BET but only explained 16% of the variation in rectal BET. Conclusions These observations provide normal values for anorectal pressures by HRM. Increasing age is associated with lower anal resting pressure, a more positive rectoanal gradient during simulated evacuation, and a shorter BET in asymptomatic women. While the rectoanal gradient is negatively correlated with rectal BET, this gradient is negative even in a majority of asymptomatic women, undermining the utility of a negative gradient for diagnosing defecatory disorders by HRM.

The majority of patients with EGJOO and HE appear to have a benign clinical course similar to controls in the absence of specific treatment. However, the combination of abnormal IRP and DCI in both HE and EGJOO appears to discriminate an important subset of patients who may benefit from treatment. Further refinement of manometric criteria may therefore provide more useful clinical definitions of EGJOO and HE.

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