Young adults who do regular fitness training have a higher IQ and are more likely to go on to university, research has suggested.

The study published in the journal Proceedings of the National Academy of Sciences (PNAS) showed those with good physical fitness obtained better results on an IQ test.

However, scientists were quick to point out that it is only fitness that appears to play a role in better IQ test results, and not strength.

"Being fit means that you also have good heart and lung capacity and that your brain gets plenty of oxygen," said Michael Nilsson, professor at the Sahlgrenska Academy and chief physician at the Sahlgrenska University Hospital, the two institutions which carried out the research.

"This may be one of the reasons why we can see a clear link with fitness, but not with muscular strength."

According to Mensa, the average IQ score is 100.