Spending a lot of time driving may actually put your brain in reverse.

A new British study found that spending more than two hours a day behind the wheel steadily lowers IQ, especially in middle-aged drivers, according to the Sunday Times of London.

Driving is physically and mentally sedentary and can cause stress and fatigue, all factors in brain decline, experts told the newspaper.

“Staying mentally and physically active helps keep our brains healthy, so it is not surprising,” researcher Rosa Sancho said.