But the maximum benefit seems to be obtained from 14 hours of sport a week, which is double the official recommendation of seven hours for this age group, the study shows.
The researchers quizzed more than 1,200 sixteen to twenty year olds in the French speaking part of Switzerland between February 2009 and January 2010 about how much sport they did.
Their mental and physical wellbeing was assessed using validated scoring criteria from the World Health Organization, on a scale of 0 to 25. A score below 13 indicates poor wellbeing.