Does Exercise Really Boost Your Mood?

From the NY Times online…

April 27, 2011, 12:01 am

Does Exercise Really Boost Your Mood?

By GRETCHEN REYNOLDS

There exists a large and soothing body of scientific literature suggesting that regular exercise can improve someone’s mood and fight anxiety. And then there is this experiment from Germany, in which researchers placed running wheels in the cages of a group of laboratory mice and let them exercise at will.

Mice generally love to run, and these rodents spent almost every waking hour on their wheels, skittering through more miles than most animals are allowed to complete during exercise studies, averaging about seven miles per mouse per day. The scientists, from the Central Institute of Mental Health at the University of Heidelberg, then placed these avid runners in unfamiliar situations. What they found was surprising, in part because it contradicted earlier experiments by other researchers. The mice froze or quickly fled to dark corners, behaviors considered by some researchers to signify anxiety. It was as if the marathon runners in this experiment had become more anxious and neurotic than the nonrunners, presumably because of the volume of their running.

Read on here.