Target Physiotherapy Versus Exercise Support Intervention for Bladder-bowel Dysfunction in Adolescents With Obesity

Obesity in adolescence is a major public health challenge and is associated with a broad spectrum of metabolic, psychological, and functional complications. While considerable attention has focused on cardiometabolic consequences, bladder-bowel dysfunction (BBD) remains an underrecognized comorbidity in adolescents with obesity. BBD is characterized by the coexistence of lower urinary tract symptoms and bowel dysfunction, particularly functional constipation, in the absence of neurological or anatomical abnormalities. Symptoms may include urinary urgency, daytime urinary incontinence, nocturnal enuresis, infrequent voiding, constipation, and fecal incontinence, all of which can substantially impair health-related quality of life, psychosocial functioning, and participation in school and social activities.

Current evidence suggests that obesity may contribute to the development and persistence of BBD through multiple interacting mechanisms. Increased intra-abdominal pressure may impair pelvic floor and bladder function, while sedentary behavior, inadequate dietary habits, insufficient hydration, and reduced physical activity may contribute to functional constipation and altered bowel habits. Obesity is also associated with chronic low-grade inflammation, sleep disturbances, and psychosocial stress, factors that may further influence bladder and bowel function. Despite growing evidence supporting an association between obesity and BBD, most available studies are observational, and prospective intervention studies targeting both conditions simultaneously are lacking.

Current international recommendations identify standard urotherapy and bowel management as first-line conservative treatment for non-neurogenic bladder-bowel dysfunction in children and adolescents. These interventions aim to modify voiding and bowel habits, optimize hydration, improve toileting posture, reduce dysfunctional elimination behaviors, and restore normal pelvic floor function. Physiotherapy techniques, including pelvic floor muscle training, breathing exercises, lumbo-pelvic mobility exercises, and behavioral education, are increasingly incorporated into multidisciplinary continence management. However, the effectiveness of these approaches has not been specifically evaluated in adolescents with obesity.

Physical exercise may also represent a clinically relevant intervention for BBD. Besides its established role in obesity management, regular physical activity has been associated with lower rates of constipation and may improve several obesity-related mechanisms potentially involved in bladder and bowel dysfunction, including sedentary behavior, sleep quality, systemic inflammation, psychological health, and body composition. Nevertheless, no randomized controlled trials have prospectively evaluated whether structured exercise programs improve bladder-bowel dysfunction in adolescents with obesity.

The OBE-BBD trial was designed to address this important evidence gap. The study is a single-center, parallel-group, three-arm randomized controlled trial conducted at the Pediatric Outpatient Clinic of the Department of Pediatrics, Hospital de Santa Maria, Unidade Local de Saúde de Santa Maria, Lisbon, Portugal.

Adolescents aged 13 to 18 years receiving multidisciplinary treatment for obesity will be invited to participate. After baseline assessment, eligible participants will be randomly allocated in a 1:1:1 ratio to one of three study groups: (1) target physiotherapy integrated with urotherapy and bowel management in addition to usual obesity care; (2) an exercise support intervention in addition to usual obesity care; or (3) usual obesity care alone.

Both active interventions will be delivered over a 12-week period between routine obesity clinic visits.

The target physiotherapy program combines standardized urotherapy education, bowel-management strategies, pelvic floor muscle training, diaphragmatic breathing, lumbo-pelvic mobility exercises, stretching, strengthening exercises, and a structured home-based exercise program.

The exercise support intervention is designed to reinforce adherence to physical activity recommendations routinely prescribed during obesity treatment through supervised exercise sessions and a standardized home-based high-intensity interval training (HIIT) program specifically adapted for adolescents with obesity. The exercise intervention intentionally excludes any educational or behavioral content specifically addressing bladder or bowel dysfunction in order to isolate the effects of exercise itself.

Participants allocated to the control group will continue to receive the standard multidisciplinary obesity management routinely provided at the clinic, including pediatric, nutritional, and exercise counseling. To avoid contamination between study arms, participants in the exercise intervention and usual care groups will not receive targeted bladder-bowel dysfunction education or treatment during the intervention period unless clinically required for safety.

Participants requiring urgent management due to clinically significant deterioration will receive appropriate medical care according to standard clinical practice.

The primary objective of the trial is to determine whether either target physiotherapy or the exercise support intervention reduces bladder-bowel dysfunction symptom severity compared with usual obesity care. Secondary objectives include evaluating the effects of the interventions on urinary symptoms, functional constipation, urinary incontinence, enuresis, urinary tract infections, health-related quality of life, psychological functioning, physical activity, sedentary behavior, sleep, dietary habits, body composition, and obesity-related outcomes. The study will also investigate whether improvements in lifestyle behaviors or obesity-related characteristics mediate changes in bladder-bowel dysfunction symptoms.

Participants will undergo evaluations at baseline, immediately after completion of the 12-week intervention, and three months after the end of the intervention to examine both short-term and sustained effects.

Outcome assessment includes validated patient-reported questionnaires, clinical evaluation, objective anthropometric measurements, accelerometry, dietary assessment, and routinely collected clinical information.

The study is expected to provide the first randomized evidence comparing targeted physiotherapy and structured exercise support as non-pharmacological strategies for improving bladder-bowel dysfunction in adolescents with obesity. The findings may contribute to the development of integrated multidisciplinary treatment approaches that address both obesity and functional bladder-bowel disorders, with the potential to improve physical health, psychological well-being, and quality of life in this vulnerable population.

Inclusion criteria

• Male or female adolescents aged 13 to 18 years.
• Obesity defined as BMI z-score ≥2, according to the WHO growth reference for school-aged children and adolescents.
• Currently receiving obesity treatment at the Pediatric Outpatient Clinic, Department of Pediatrics, Hospital de Santa Maria, Unidade Local de Saúde de Santa Maria, Lisbon, Portugal.
• Able to understand the study procedures and comply with study requirements.
• Written informed consent provided by a parent or legal guardian.
• Written assent provided by the adolescent.

Exclusion criteria

• Known neurological disorder affecting bladder or bowel function.
• Structural urinary tract or gastrointestinal malformation.
• Previous pelvic surgery affecting urinary or bowel continence.
• Diabetes mellitus or uncontrolled endocrine or monogenic disorders affecting obesity or bladder/bowel function.
• Severe psychiatric disorder requiring immediate specialized treatment and likely to interfere with study participation or adherence.
• Major orthopedic or musculoskeletal condition preventing safe participation in the exercise intervention.
• Current participation in another interventional clinical trial.