Driving for more than two hours a day negatively affects IQ levels， scientists have warned.英语散文
news for aged' target='_blank'>middle-， a recent study found that long periods behind the wheel could speed up the effects of age on the brain.
The researchers said 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.
studies have found that long periods of inactivity have a detrimental affect on brainpower and Dr Bakrania39;s research shows similar results for those who watched more than two hours of television a day.
actually boosted people39;s cognitive stills， leading the scientist to propose another potential factor for driving39;s negative effects.
39; stresses and fatigue， with studies showing the links between them and cognitive decline.39;