London, Dec 6 (IANS) Does being in peak physical condition ensure higher IQ levels? A study involving 1.2 million Swedish soldiers born between 1950 and 1976, shows a clear link between fitness and mental calibre.
The strongest links are for logical thinking and verbal comprehension. But it is only fitness that plays a role in the results for the IQ test, not strength.

“Being fit means that you also have good heart and lung capacity and that your brain gets plenty of oxygen,” says Michael Nilsson, professor at the Sahlgrenska Academy and chief physician at the Sahlgrenska University Hospital, Sweden.

“This may be one of the reasons why we can see a clear link with fitness, but not with muscular strength. We are also seeing that there are growth factors that are important,” adds Nilsson.

By analysing data for twins, the researchers have been able to determine that it is primarily environmental factors and not genes that explain the link between fitness and a higher IQ.

“We have also shown that those youngsters who improve their physical fitness between the ages of 15 and 18 increase their cognitive performance,” says Maria Åberg, researcher at the Sahlgrenska Academy.

“This being the case, physical education is a subject that has an important place in schools, and is an absolute must if we want to do well in maths and other theoretical subjects,” adds Aberg, according to a Sahlgrenska Academy release.

The researchers have also compared the results from fitness tests during national service with the socio-economic status of the men later in life. Those who were fit at 18 were more likely to go into higher education, and many secured more qualified jobs.

The link between physical fitness and mental performance has previously been demonstrated in studies carried out on animals, children and old people.

The results were published in the Proceedings of the National Academy of Sciences.