Common sense tells us that people seek pleasure and avoid pain. But that’s not always the case – various activities involve pain, including running, hot massages, tattoos, piercings and even BDSM (an abbreviation for bondage, discipline, domination, submission, sadism and masochism).

For McNabb, the pain from the peppers produces a rush that is similar to that produced by food, drugs or sex. “The pain subsided pretty quickly and then it was just the high of the adrenaline and euphoria from the peppers,” Jason explains.

The link between pleasure and pain is deeply rooted in our biology. For a start, all pain causes the central nervous system to release endorphins – proteins which act to block pain and work in a similar way to opiates such as morphine to induce feelings of euphoria.

The relationship will come as no surprise to those who run. Bursts of intense exertion release lactic acid, a by-product of the breakdown of glucose when oxygen is in short supply. The acid irritates pain receptors in the muscles, and these communicate their plight to the brain through electrical messages, sent through the spinal cord. The signals are interpreted as a burning sensation in the legs, usually causing the runner to slow down or stop.