['1) Describe and compare evolutionary features of the pyrosis symptom with a positive acid perfusion test in the entire study population, and divided by sex. 2) Describe the results of different tests according to sex (standard acid clearance, number of reflux episodes in a short testing period, period of time until the appearance of pyrosis during acid perfusion, period of time until its disappearance, and esophagus pH at the time). 3) Compare differences between control and patient cases regarding standard clearance and reflux episodes. 4) Establish a multivariance correlation between the results of the tests according to sex and historical data, looking for one or more regulating factors. 5) Establish the same descriptive and comparative assessments in both subgroups, with and without hiatal hernia (HH).', '15 healthy subjects, 9 men and 6 women (control), and 50 patients with pyrosis, 23 men and 27 women, over 18 years old, with or without HH, matched for age and sex (p = NS), and consecutive.', 'Clinical data records, esophagogastroendoscopy with at least three biopsy samples, number of reflux episodes within 30 minutes, standard acid clearance, measurement of perfusion time, time it takes pyrosis to disappear, and esophagus pH at the time. This is a prospective, descriptive, comparative, experimental, longitudinal, single-blind study with control subjects.', 'Eighty-two percent (82%) of the study population had pyrosis II. Average age: 39.9 +/- 13.3 years, with no differences between sexes (p = 0.31). Development period at study time: 5.7 +/- 5.5 years (p = 0.33). Fifty-eight percent (58%) of patients showed endoscopic signs of esophagitis, and 52% had HH. The number of reflux episodes, and of deglutitions needed to reach a pH of up to 5 were statistically different between patients and control subjects (p = 0.0005). The time required by acid perfusion for pyrosis to recur was 3.67 +/- 3.26 minutes. The time until its disappearance was 2.2 +/- 1.78 minutes. pH at pyrosis spontaneous cessation was 2.10 +/- 0.83. There was a correlation between the age at the time the symptom appeared, and the time the induced pyrosis disappeared (p = 0.02), as well as between this point in time and its corresponding pH (p = 0.006, r = 0.45). The presence of HH was associated with the number of reflux episodes and the frequency of proven endoscopic injuries, but not with the other parameters.'] Is [ The time and pH at the moment of disappearance of pyrosis induced by of esophagus acid perfusion an indicator of hyperalgesia ]?