Each song lasts as long as the lead singer can hold his or her breath.

UNESCO: CULTURE

This can lead to a condition called "ketosis", which can cause bad breath, nausea and a bad taste in the mouth.

BBC: Health risk of 'faddy diets'

The breath-test technology relies on the idea that the biology of tumours can lead to the production of specific "volatile organic compounds", combinations of chemicals unlikely in a healthy person.

BBC: 'Promising results' for bowel cancer breath-test