The Effect of Intensive Physical Exercise on Fatigue and Quality of Life in Patients With Quiescent Inflammatory Bowel Disease (ENERGIZE-IBD)

Inclusion Criteria: ≥1 year diagnosis of IBD, including Crohn's disease (CD), ulcerative colitis (UC) and IBD-unclassified (IBD-U), based on a combination of clinical, endoscopic, histologic and radiologic internationally accepted criteria; Chronic fatigue complaints for at least 3 months; Severe fatigue complaints as confirmed with a score of ≥11 on section I of the inflammatory bowel disease fatigue self-assessment scale (IBD-F); Clinically quiescent IBD with a Harvey Bradshaw Index (HBI) <5 for Crohn's disease patients or a Simple Colitis Clinical Activity Index (SCCAI) ≤2 for patients with ulcerative colitis or IBD-unclassified; Faecal calprotectin <100 μg/g; Stable medication for at least 3 months before screening visit; Patient is able and willing to provide written informed consent; Patient is able/commitment to make a time investment to complete the intervention program (one hour training 3x/week during 12 weeks) or, after randomisation, willing to participate in the control group; Patient is aged between 18 and 60 years. Exclusion Criteria: Performing moderate-vigorous intensity exercise (i.e. swimming, running, cycling) more than once and/or >90 minutes per week in the past 3 months; Surgery within the past 6 months or planned surgery within 12 months after the screening visit; Participation in another intervention study; Pregnant at the moment of the screening visit or planning pregnancy within 12 months after the screening; Confirmed diagnosis of other causes of fatigue complaints, such as thyroid dysfunction, liver or renal failure, anaemia, folate-, iron-, vitamin B12- or D deficiency. Comorbidities that could be confounders for fatigue, such as Chronic obstructive pulmonary disease (COPD), heart failure, active malignancy, long/Post-COVID and patients under treatment for a psychiatric disorder (i.e. depression/anxiety) Comorbidities that prevent safe participation in the exercise program/cardiorespiratory fitness test including; Very high risk of cardiovascular disease Uncontrolled diabetes mellitus with HbA1c > 65 mmol/l. Cardiovascular disease (i.e. acute myocardial infarct, unstable angina, uncontrolled arrhythmias, aortic stenosis, stenotic valvular heart disease, untreated arterial hypertension (>200 mmHg systolic, >120 mmHg diastolic)) Acute non-cardiopulmonary disorder that may affect exercise performance or be aggravated by exercise (i.e. infection, thyrotoxicosis) Uncontrolled asthma Pulmonary oedema Significant pulmonary hypertension Acute pulmonary embolus or pulmonary infarction Room air desaturation at rest <85% (exercise with supplemental O2) Respiratory failure Electrolyte abnormalities (sodium, potassium, calcium, magnesium) Mental impairment leading to inability to cooperate Orthopaedic impairment that compromise exercise performance BMI ≥35