Jonesin' for some Joggin'.

As it turns out, "runner's high" is more potent then previously thought. According to a study in the August edition of the journal Behavioral Neuroscience, the addiction is downright heroin-like.

From ABC News:

To test this, scientists turned to rats. It turns out rodents also keep increasing their amount of time on the running wheel like humans do.

Researchers at Tufts University let one group of rats become increasingly avid runners, and forced another group of rats to stay lazy in a cage with no hamster wheel.

When the researchers injected both groups of mice with a drug called Naloxone that is used for heroin withdrawal, the rats who had become exercise fanatics showed withdrawal symptoms similar to human heroin addicts on Naloxone -- their teeth shattered, and their bodies shook in tremors.

The unexercised mice, however, did not react to the Naloxone.

Shattered teeth? That's good to know. Next time you want to mess with your runner friends, slip them a little Naloxone.

I wonder how long it's going to take Lou Reed to write a song about marathons.