A new Swedish study finds that young adults who are fit have a higher IQ and are more likely to go on to college.

As Sweden has a mandatory military commitment, investigators evaluated information on 1.2 million Swedish men who were born between 1950 and 1976. The research group analyzed the results of both physical and IQ tests when the men enrolled.

The study shows a clear link between good physical fitness and better results for the IQ test. The strongest links are for logical thinking and verbal comprehension. However, only cardiovascular fitness played 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.

“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.”

By analyzing 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 and physician at Åby health centre.

“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.”

The researchers have also compared the results from fitness tests during national service with the socioeconomic 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.

However, studies on young adults have been contradictory to date. Around the age of 20 human brains may still change rapidly as a result of both cognitive and emotional development.

The study was carried out at the Center for Brain Repair and Rehabilitation in Gothenburg in conjunction with the Swedish Twins Registry at the Karolinska Institutet.

Source: Karolinska Institutet