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Walking exercise improves bowel preparation before colonoscopy

BMJ 2005; 331 doi: (Published 01 December 2005) Cite this as: BMJ 2005;331:0-e

Research question Can gentle exercise improve the quality of standard bowel preparation before colonoscopy?

Answer Yes. Patients who walk intermittently while taking bowel preparation solution have cleaner bowels than patients who sit still.

Why did the authors do the study? Poor bowel preparation is a leading cause of failed colonoscopy. Animal studies have shown that exercise can enhance bowel movement. These authors wanted to find out if gentle exercise would help patients clear their bowels before a colonoscopy.

What did they do? Three hundred and eighty three outpatients from South Korea took part in a single blind randomised controlled trial of standard bowel preparation for colonoscopy with or without gentle exercise. All the participants had a liquid dinner the evening before their colonoscopy and 5 mg of bisacodyl as a premedication followed by 2.5 to 3.0 litres of polyethylene glycol on the day. Those randomised to exercise took the solution in 250 ml doses and walked around for at least five minutes after each dose. Control patients took 250 ml of polyethylene glycol every 10 minutes and rested between doses. Patients in the two groups were well matched for age, sex, body mass index, bowel habit, and interval between bowel preparation and colonoscopy (about 4.5 hours). Three hundred and fifty six patients contributed data to the final analysis. All participants had the same endoscopist, who rated the quality of bowel preparation according to a four point scale: 1 (excellent), 2 (good), 3 (fair), or 4 (poor). The endoscopist remained unaware of treatment allocation. At the end of the trial, the authors looked for a difference in scores between the two groups of patients. They also did a multivariate analysis to find out which factors (including the type of bowel preparation) were associated with a cleaner bowel.

What did they find? Patients who had walked around during their bowel preparation had significantly cleaner bowels than control patients: 41% (74/182) of the exercise group and 25% (44/174) of the control group had good or excellent bowel preparation, according to the endoscopist. Overall, the exercise group had a lower (better) mean bowel preparation score than the control group (2.59 v 2.76, P = 0.005). Exercise seemed to work for patients with or without a history of constipation. In the multivariate analysis, walking during bowel preparation doubled the chance of a good or excellent result, compared with resting (odds ratio 2.06, 95% CI 1.29 to 3.29; P = 0.003.). The authors conclude that walking can help with standard bowel preparation in outpatients having a colonoscopy

What does it mean? This is the first trial to test the theory that exercise can help clean out patients' bowels before a colonoscopy. The effects were modest but clinically worthwhile, and were achieved without too much inconvenience for patients. If other studies confirm these promising results, this cheap simple intervention would be easy to incorporate into the routine of bowel preparation for fit outpatients having an elective colonoscopy. Sicker patients, who may be harder to prepare than others, were excluded from this study.

Kim et al. Effectiveness of walking exercise as a bowel preparation for colonoscopy: a randomized controlled trial. American Journal of Gastroenterology 2005;100: 1-6.

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