From his archive page of this past wk. Was rather interesting, thought I'd pass it along.
Source:
http://www.townhall.com/talkradio/show.aspx?radioshowid=3Tuesday July 22, 2008
Prager H1: Your Brain on Exercise With Dennis Prager
Prager H1: Dennis talks to John J. Ratey, MD, clinical associate professor of psychiatry at Harvard Medical School. His latest book is Spark: The Revolutionary New Science of Exercise and the Brain. A Best of Prager Hour. Originally broadcast on February 12, 2008.

Length: 00:34:27
(BTW - Sometimes there's a lead-in ad, just ignore it - the rest of the program is w/o ads at the normal radio station-breaks)