Closeness between couples is reflected in the distance separating them as they sleep, a study has found.
Partners who slept less than 2.5cm apart were more likely to be happy with their relationship than those maintaining a gap wider than 76cm.
In addition, more couples who spent the night making physical contact were happy than those with a "no touching" rule while trying to sleep.
The survey of 1000 people, conducted as part of the Edinburgh International Science Festival, also revealed the most popular sleep positions of couples, with 42 per cent lying back to back, 31 per cent facing the same direction and four per cent facing one another.
Twelve per cent of couples spent the night less than 2.5cm apart, while just 2 per cent were separated by more than 76cm.