Most people get it that a sedentary lifestyle is bad for the body; now comes news that it’s also bad for the brain, and in turn, for the body. Gretchen Reynolds reports in the New York Times on research conducted at Wayne State University School of Medicine that put a dozen rats in cages with running wheels and a dozen rats in cages with no wheels. Three months later, the researchers examined the rats’ brains, paying particular attention to the rostral ventrolateral medulla, which Reynolds describes as “an obscure portion of the brain that controls breathing and other unconscious activities central to our existence.” What did they see? Reynolds reports that the neurons in the brains of the running rats were were functioning normally, but many of the neurons in the brains of the sedentary rats had sprouted many new tentacle-like arms known as branches,–normally a good thing, except that these neurons had more branches than normal, making them more sensitive to stimuli and apt to zap scattershot messages into the nervous system. Not a good thing. The researchers believe that the neurons changed in ways that made them likely to overstimulate the sympathetic nervous system, potentially increasing blood pressure and contributing to the development of heart disease. Read more in the New York Times.