EXERCISE CALMS THE BRAIN

Exercise is known to combat anxiety, but scientists have long been puzzled by why that’s so. Physical activity creates excitable new neurons in the hippocampus—a part of the brain that regulates emotion, thinking, and memory—and in theory, having more of these neurons should make people more anxious. (click below to read more)

 But when Princeton researchers compared the neurons grown in the brains of mice that regularly ran on a wheel with those in sedentary mice, CBSNews.com reports, they found that the active mice gained more of a particular type of neuron that releases the neurotransmitter GABA, which keeps other young neurons from becoming overactive. When both groups of mice were exposed to stress—in the form of a cold bath—their excitable neurons lit up as expected. But unlike the sedentary mice, the fit mice also released a large amount of GABA, which quickly quelled their anxiety. Researchers think routine exercise changes human brains similarly, helping us relax in the face of stress.