Japanese boffins claim to have proof that spending hours playing video games can damage your health.

A study of 240 people, conducted by professor Akio Mori of Nihon University, showed that prolonged playing can cause stress and a loss of concentration.

The work focused specifically on the prefrontal region of the brain, which governs emotion and creativity.

Those who played video games the longest showed lasting ill effects, and ended up using less of their brains even after they had finished.

Professor Mori told the Mainichi Daily News: "Many video games stir up tension and a feeling of fear, and there is concern that this could have an effect on the autonomic nerves.

"During childhood, playing outside with friends, not video games, is the best option."

The report is to be presented to the Society for Neuroscience in the US later this year.