Influence of esophageal pH recording on physical activity in children

Twenty-four-hour pH-metry represents the gold standard for the diagnosis of gastroesophageal reflux. Ambulatory esophageal pH recording provides a better reflection of occurrences under normal domestic living conditions, but it may influence physical activity. The aim of this study was to assess the influence of ambulatory esophageal pH recording on physical activity in children.

This prospective study included 22 patients (18 boys, 4 girls) 3 to 15 years old (mean age 6.9 +/- 2.3 years) who had been referred for ambulatory pH-metry. The 24-hour physical activity was measured twice in each child using a triaxial accelerometer 1 week before or after pH-metry and during pH-metry. Levels of intensity of physical activity (low: sedentary activities; moderate: walking; high: intense activities such as jumping, running, and sport) were compared by the paired nonparametric Wilcoxon test.

Physical activity was 53% lower during 24-hour pH-metry than when it was not present (P < 0.0005). The duration of low-level physical activity was longer during pH-metry (84% vs 73%; P < 0.01). The duration of moderate-intensity and high-intensity physical activity was shorter during pH-metry (16% vs 24% and 0.2% vs 2.2%, respectively; P < 0.005 and P < 0.0001).

Ambulatory 24-hour esophageal pH recording substantially decreases physical activity, mainly high-level physical activity. Whether such changes in activity decrease the sensitivity of pH-metry and lead to false negative results in some children remains to be assessed.