Driving for more than two hours a day negatively affects IQ levels, scientists have warned.
In what might come as unwelcome news for middle-aged commuters, a recent study found that long periods behind the wheel could speed up the effects of age on the brain.
The researchers that the results could be explained by the fact that the mind is less active on long car journeys.
The mammoth project saw more than half a million Britons aged 37-73 studied over a period of five years.
Out of these some 93,000 of them drove more than two or three hours a day.
Researchers found that not only did this proportion of subjects typically have lower brainpower to begin with but their IQ score declined more rapidly over the course of the study than those who did little or no driving.
Kishan Bakrania, a medical epidemiologist at the University of Leicester, told The Sunday Times: ‘We know that regularly driving for more than two or three hours a day is bad for your heart.
‘This research suggests it is bad for your brain too, perhaps because your mind is less active in those hours.’
Previous studies have found that long periods of inactivity have a detrimental affect on brainpower and Dr Bakrania’s research shows similar results for those who watched more than two hours of television a day.
But the study also found using computers actually boosted people’s cognitive stills, leading the scientist to propose another potential factor for driving’s negative effects.
‘Driving causes strees and fatigue, with studies showing the links between them and cognitive decline.’