Endurance athletes sometimes say they're "addicted" to exercise. In fact, scientists have shown that rhythmic, continuous exercise — aerobic exercise — can in fact produce narcoticlike chemicals in the body.

Now researchers suggest that those chemicals may have helped turn humans, as well as other animals, into long-distance runners.

The man behind the research is University of Arizona anthropologist David Raichlen, a runner himself. He does about 25 miles a week.

When it comes to walking, the easy part is understanding the benefits: Regular, brisk walks can strengthen our bones, help control blood sugar, help lower blood pressure and cholesterol, and the list goes on. The hard part is finding the time to fit it in.

Engineering physical activity back into Americans' daily lives is the goal of an educational campaign launched by Kaiser Permanente,an Oakland, Calif.-based health plan.

Somewhere on the path to the White House this year, a powerful set of ideas began to creep into the mainstream debate over which direction the country will take.

These are ideas that not too long ago were written off as marginal, or even worse, a little kooky. They come from Libertarians: free and open markets and extremely limited government. Those ideals are now becoming more mainstream and are influencing the Republican Party.

Hazing is in the news again this week, and researchers say there might be more of it than there used to be. But New Hampshire Public Radio's Dan Gorenstein reports it is also getting more attention, and that could be a very good thing.

Transcript

GUY RAZ, HOST:

It's WEEKENDS on ALL THINGS CONSIDERED from NPR News. I'm Guy Raz.

In France, the voters have spoken: a new president elected today and his name is Francois Hollande.

PRESIDENT-ELECT FRANCOIS HOLLANDE: (Foreign language spoken)

(SOUNDBITE OF CHEERS AND APPLAUSE)

Transcript

(SOUNDBITE OF CLOCK TICKING)

GUY RAZ, HOST:

She closed the book, placed it on the table and finally decided to walk through the door. That's the starting sentence for Round 8 of Three-Minute Fiction. That is our contest where we ask you to write an original short story that can be read in about three minutes. We are no longer accepting submissions for this round.

Our readers from across the country are almost done going through all of the more than 6,000 submissions this round. So let's hear a few samples of their favorites so far.

According to exit polls, angry Greek voters have overwhelmingly punished the two major parties that endorsed draconian international loan agreements.

There is no front-runner in sight, but the fringe parties on the left and the right that strongly oppose the bailout terms have benefited the most.

The socialist PASOK and the conservative New Democracy parties that have alternated for four decades — and uneasily co-governed for the last six months — are imploding.