I couldn’t resist this one. Seems a recent study has show incontrovertibly that the mere anticipation of having a laugh reduces stress hormones. In their earlier work, the same researchers had found that just thinking of laughing increased health-protecting hormones like endorphins (that alleviate depression) and human growth hormone (that boosts immunity).

So now you know when a trainer comes in and tries to get people to laugh, or a politician has writers put lots of funny stuff into a speech, it’s not just about “breaking the ice”—participants who are less stressed will literally react more openly to what’s presented. What’s more, and of course this is my extrapolation, people receiving email jokes at work can be expected to experience these little boosts in good stuff and reductions in bad stuff—which is bound to contribute to increased productivity, despite the few minutes used “non-productively” to review the jokes.

Anyway, here’s the study, so you can draw your own conclusions.