A systematic and critical review of measurement scales for evaluating gastrointestinal symptoms during exercise

Exercise-induced gastrointestinal symptoms (GIS) are commonly reported, with either Likert-type scales or visual analog scales (VAS) used to quantify the incidence and magnitude of symptoms. However, these measurement tools lack consistency in their design, reporting, and key aspects such as the validity of these tools is unclear. This study aimed to systematically review and critically discuss the various Likert-type and VAS scales used to assess GIS during exercise.

A search conducted in August 2025, in accordance with PRISMA guidelines, identified full-text articles evaluating GIS during exercise or sport.

In total, 126 studies were included, representing 50 different scales and 13 scale lengths. The most frequently used measures were 11-point Likert-type scales and VAS (46%). Only one study assessed the reliability of an 11-point exercise-specific scale, and only one study used a validated retrospective questionnaire developed for assessing chronic GIS in runners. Most studies (92%) did not justify their scale selection, often adapting tools from non-exercise contexts or using custom-designed measures.

The current review highlights substantial heterogeneity in GIS measurement during exercise and a paucity of evidence on validity and reliability. In addition to identifying current methodological limitations, the current review provides practical recommendations to support improved GIS assessment and reporting in exercise settings. The development of a standardized, fully validated exercise-specific GIS scale remains a priority, as current tools range from those with limited (partial) psychometric evaluation to those with no formal validation evidence, thereby limiting consistency, reliability, and comparability across studies and in practice.