A leaky gut is just that: our intestinal barrier weakens and allows bacteria into the bloodstream. And people who have hostile and angry confrontations with their partner end up with more bacteria in their blood, suggesting the upset has made the gut leaky.

Researchers from the Ohio State University tested the theory on a group of 43 healthy married couples. They were asked to talk about a sensitive issue, such as money or the in-laws, and they were observed via a video camera. Blood samples were taken before and after the argument, and the couples whose arguments became the most heated were also the ones with the highest levels of bacteria in their blood. In fact, the ones who had the most hostile confrontations had 79 per cent more bacteria in their blood than those who had a more equitable discussion.