New study sheds light on exercise's impact on brain

(CBS News) Exercise can lower anxiety, but how it does so remains a mystery. Now, a new study conducted at Princeton University, published in the Journal of Neuroscience, may offer clues as to what happens in the brain.

Conducted on mice, the study was done on two groups of the animals. The first group was was given a good amount of exercise and the other was more sedentary. Upon studying their brains, researchers found both groups had formed new brain cells called neurons, but the exercisers formed more neurons that release the neurotransmitter GABA, which has a calming effect on the brain.

Dr. Holly Phillips noted on "CBS This Morning," that GABA is known to reduce anxiety. In fact, many prescription anxiety drugs cause the brain to release GABA. "These cells help to calm down the brain and hence fight anxiety," she said.

It's also likely, Phillips said, that the results will translate very well into humans. She said, "We've suspected for a very long time that GABA would, of course, be involved and now, there's just extra (evidence) of that."

Exercise actually changes the brain permanently, Phillips pointed out. It changes the types of cells that are there. Phillips added, "This is important because then it has lasting effects. Even 24 hours after exercise, you're less prone to experience anxiety symptoms."

Phillips says exercising 30 minutes four days a week can help, based on other studies on exercise.

She added, "For anxiety in particular, high-intensity exercise is really important and also we're always looking for natural alternatives. Some of the anti-anxiety medications can be habit-forming and anytime we can do something where we don't need to take a medication, of course, is a good thing."

Watch Dr. Holly Phillips' full segment above.