IBD patients can benefit from moderate, low-impact exercise
Physical activity is an important component of a healthy lifestyle. Exercise helps adults lose or maintain a healthy weight, relieves stress (by releasing endorphins, which are "feel-good" hormones), and helps strengthen the body’s immune system.  But what about people with inflammatory bowel disease (IBD)? Research shows that for most IBD patients, regular exercise leads to good health and that IBD patients may experience additional benefits such as minimizing extraintestinal symptoms of the disease.  Regular exercise can also improve your psychological health by reducing depression and anxiety.
However, there may be times when you may not feel up to exercising. It’s best that you limit exercise during any flare-ups. You can resume your activities once the flare-up is under control and you are eating more regularly and have more energy. Discuss with your physician what IBD exercises are best for you and your abilities. In general, physicians recommend low-impact aerobic activities (such as brisk walking, bicycling or swimming) for patients with IBD. Another helpful hint: plan routes that allow for bathroom breaks if necessary. Also, if you find different activities that you enjoy, try switching on and off between them, depending on how you are feeling.
CDC: Physical activity for everyone
 Neeraj Narula, BSc and Richard N Fedorak, MD, Exercise and inflammatory bowel disease, Canadian Journal Gastroenterology. 2008 May; 22(5): 497-504.