This is usually due to relaxation of the abdominal muscles in an unconscious attempt to relieve discomfort. The distension usually disappears on lying flat or on contracting the abdominal muscles. A high fibre diet is responsible for bloating in some people but generally the bloating improves with time. On the other hand, a high fibre diet may relieve bloating in others because fibre absorbs water in the gut and gently distends it helping to prevent the unco-ordinated contractions that are partly responsible for the bloating. An irritable bowel may be caused by stress or anxiety so that stress may be responsible for your bloating.
Some people find that activated charcoal or defoaming agents containing simethicone are helpful.
If the bloating is severe your doctor may prescribe drugs that help to co-ordinate the contractions of the gut or prevent spasms. Bloating due to a build up of gas occurs in intestinal diseases such as Crohn's disease or bowel tumour. These conditions give rise to other symptoms such as weight loss, severe abdominal pains or diarrhoea and require prompt medical investigation. Bowel noises or borborygmi are produced when the liquid and gas contents of the intestine are shuffled backwards and forwards by vigorous contractions of the gut. Loud borborygmi or rumblings also occur because of vigorous contraction caused by diseases of the intestine like Crohn's disease or to overcome obstruction.