[Sean Moore]

Sean Moore  asked the Naked Scientists:

Hey Chris,
Obviously I love the show. Only a fool couldn't.

Why do I need to spit phlegm when I'm doing a rigorous jog?

Sean Moore
-Winnipeg, Manitoba, Canada

What do you think?

[JnA]

You are breathing deeper, using your lungs more effectively (than at rest) and shifting mucous around and, as far as the lungs are concerned, the only way is up, baby.