Physical Activity and Fitness in Pediatric Inflammatory Bowel Disease

Effects of Physical Activity and Physical Fitness on Inflammation, Clinical Outcomes, and Quality of Life in Pediatric Inflammatory Bowel Disease

Pediatric inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic condition associated not only with intestinal inflammation but also with reduced physical fitness, fatigue, impaired quality of life, and psychosocial difficulties. Although physical activity and physical fitness are recognized as important determinants of health in the general pediatric population, their role as modifiable prognostic factors in children and adolescents with IBD remains insufficiently studied, particularly using objective measures and longitudinal designs in hospital settings.

The present hospital-based study aims to investigate the effects of physical activity and physical fitness on inflammation, clinical outcomes, and quality of life in children and adolescents with IBD. The project comprises three phases: (1) an observational cross-sectional and longitudinal assessment, (2) a randomized controlled trial (RCT) evaluating a structured physical activity intervention, and (3) a medium-term follow-up at 6-12 months.

Physical activity will be assessed objectively using accelerometry and subjectively using validated questionnaires. Physical fitness will be evaluated with the ALPHA fitness battery adapted to the hospital setting, with cardiorespiratory fitness assessed by the 20-meter shuttle run test as the primary outcome of the RCT. Clinical outcomes will include objective inflammatory markers (fecal calprotectin and C-reactive protein), disease activity indices (PCDAI or PUCAI), musculoskeletal health, fatigue, cognitive functioning, and health-related quality of life. Nutritional status and dietary quality will also be assessed, and selected biological markers will be analyzed in a subsample.

The RCT will examine whether a 12-week supervised physical activity program improves cardiorespiratory fitness compared with usual care, and whether changes in fitness are accompanied by improvements in inflammatory burden and patient-reported outcomes. Longitudinal analyses will explore the sustainability of these effects over time.

This study will provide comprehensive, objective evidence on the role of physical activity and physical fitness as modifiable factors in pediatric IBD. The results are expected to inform clinical practice, support the integration of structured physical activity into multidisciplinary care, and contribute high-quality data for publication in international peer-reviewed journals.

Pediatric inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic condition frequently diagnosed during childhood and adolescence. In addition to persistent intestinal inflammation, pediatric IBD is associated with reduced physical activity levels, impaired physical fitness, fatigue, musculoskeletal complaints, cognitive and psychosocial difficulties, and diminished health-related quality of life. Despite advances in pharmacological treatment, many children and adolescents continue to experience functional limitations that are not fully addressed by standard medical care.

Physical activity and physical fitness are modifiable lifestyle factors with well-established benefits in healthy pediatric populations, including anti-inflammatory effects, improved cardiorespiratory and muscular fitness, and better mental health and quality of life. However, in pediatric IBD, evidence remains limited, particularly from studies using objective measurements of physical activity and fitness, randomized controlled designs, and longitudinal follow-up in hospital-based settings. Furthermore, the relationships between physical activity, physical fitness, inflammation, clinical outcomes, and quality of life have not been comprehensively examined within a single integrated study framework.

This hospital-based study aims to evaluate the role of physical activity and physical fitness as modifiable factors influencing inflammation, clinical outcomes, and quality of life in children and adolescents with IBD. The study is conducted in three sequential phases: (1) an observational cross-sectional and longitudinal assessment, (2) a randomized controlled trial (RCT) of a structured physical activity intervention, and (3) a medium-term follow-up at 6 to 12 months.

In the observational phase, participants aged 8 to 17 years with a confirmed diagnosis of Crohn's disease or ulcerative colitis will undergo comprehensive baseline assessments. Physical activity will be measured objectively using accelerometry over seven consecutive days and supplemented by validated questionnaires. Physical fitness will be assessed using the ALPHA fitness battery adapted to the hospital environment, including cardiorespiratory fitness measured by the 20-meter shuttle run test, muscular strength, agility, and body composition. Clinical outcomes will include objective inflammatory markers (fecal calprotectin and C-reactive protein), disease activity indices (PCDAI or PUCAI), musculoskeletal health, fatigue, cognitive functioning, and health-related quality of life. Nutritional status and dietary quality will also be evaluated, and selected biological markers will be analyzed in a subsample.

In the interventional phase, eligible participants will be randomized to either a 12-week structured physical activity program or usual care. The intervention consists of supervised, age-appropriate exercise sessions combining aerobic and strength-based activities, tailored to participants' clinical status and functional capacity. The primary outcome of the RCT is the change in cardiorespiratory fitness, assessed by the number of laps completed in the 20-meter shuttle run test. Secondary outcomes include changes in inflammatory markers, disease activity indices, physical fitness components, fatigue, cognitive performance, nutritional status, and quality of life.

The follow-up phase will assess the sustainability of changes in physical activity, physical fitness, inflammation, and clinical outcomes at 6 to 12 months after baseline assessment or completion of the intervention. Longitudinal analyses will examine whether baseline and intervention-induced changes in physical activity and physical fitness predict medium-term clinical and patient-reported outcomes.

All questionnaires, cognitive assessments, and consent procedures will be administered electronically using secure institutional platforms. Data will be collected and stored in a pseudonymized manner in accordance with applicable data protection regulations.

This study is designed to provide high-quality, objective evidence on the clinical relevance of physical activity and physical fitness in pediatric IBD. By integrating functional, inflammatory, and patient-centered outcomes, the findings are expected to inform multidisciplinary care strategies and support the incorporation of structured physical activity into routine clinical management for children and adolescents with IBD.

Inclusion Criteria:

• Children and adolescents aged 6 to 17 years
• Confirmed diagnosis of Crohn's disease or ulcerative colitis
• Clinical remission or mild-to-moderate disease activity
• Medical clearance to participate in physical activity
• Ability to complete study assessments and follow-up procedures
• Written informed consent from a parent or legal guardian and assent from the participant

Exclusion Criteria:

• Severe disease activity or acute flare requiring hospitalization
• Medical contraindications to exercise (e.g., severe cardiopulmonary disease, uncontrolled anemia, significant musculoskeletal conditions)
• Major surgery within the previous 3 months
• Participation in another interventional clinical trial
• Cognitive or behavioral conditions preventing participation
• Any condition considered unsafe by the investigators or treating physician