Effect of cold stress on post-prandial lower esophageal sphyncter competence and gastroesophageal reflux in healthy subjects.

The effect of cold stress on postprandial lower esophageal sphincter competence and gastroesophageal reflux was investigated in nine healthy subjects. All subjects were studied twice in a randomized order according to a common protocol: 30 min after completion of a 700-kcal meal they put their nondominant hand in water either at 37°C (control stimulus) or at 4°C (stressful stimulus) cyclically for 20 min. Pulse rate and blood pressure rose significantly (P < 0.01) during the stressful stimulus, but remained unaffected by the control stimulus. Rate of transient lower esophageal sphincter relaxations/30 min [median (interquartile range)] was similar before and during control stimulus, 4 (2.7-5.0) and 3 (2.0-4.5), respectively, whereas it was markedly inhibited during the stressful stimulus [from 5 (3.7-6.0) to 2 (1.0-2.0); P < 0.05 vs control stimulus]. Rate of reflux episodes/30 min was also similar before and during control stimulus, 1 (0-1.2) and 1 (1.0-2.2), but fell consistently during the stressful stimulus [from 2 (0-3.2) to 1 (0-2.0); P < 0.05 vs control stimulus]. Percentage of transient lower esophageal sphincter relaxations accompanied by a reflux episode was unaffected by stress as was basal lower esophageal sphincter pressure. It is concluded that cold stress decreases the postprandial rate of transient lower esophageal sphincter relaxations and reflux episodes in healthy humans.