When we eat, the food and drink we consume is broken down by the body's digestive system €“ also called the gastrointestinal (GI) tract. The contents are mixed together, the useful nutrients are absorbed and any unwanted, leftover material is excreted.

One of the ways this process works is by a movement called 'peristalsis'. Much of the body's GI tract is effectively a tube of smooth muscle through which food passes. Peristalsis is a wave of contractions travelling along the length of this tube.

When this process occurs normally, we are not aware of it. Unfortunately, the human digestive tract can be sensitive and easily disrupted. If the muscle contractions in peristalsis occur out of sync, the normally gentle, wave-like contractions may become strong, painful cramps. This can also trigger related symptoms such as diarrhoea, constipation and gas/bloating.