And now I know:

Kevin Butler is an ergonomist for office furniture supplier Steelcase. His biggest wish for office workers: that people could appreciate their anatomy.

"Something as subtle as a 10% increase in the bend of the wrist doubles the pressure on the wrist," he says. "Not knowing that, people will say, 'I can't feel these four fingers,' and by then they're stuck in this vicious cycle, because they need to use their computer, they need to work. That cycle comes from not having enough appreciation of the way we're built."

That wrist bend, he says, is the biggest predictor of the dreaded Carpal Tunnel Syndrome. According to the New York Times Health guide, 3% of women and 2% of men will get diagnosed with it.

The carpal tunnel protects the median nerve, except when it doesn't.via WikipediaThe carpal tunnel is a thin ligament-and-bone passageway at the base of the hand. One of its main jobs is to protect the median nerve, which runs down from your shoulder, through your wrist at the carpal tunnel, and into the hand, where it connects with every finger but the pinky.

But if you give those ligaments lots of low-grade pressure--like with awkward posture or resting your palms on the keyboard--they can become inflamed. That puts pressure on the medium nerve, which begets the tingly, burning pain.

"If you have tingling," Butler says, "that's a nerve being compressed."

As University of California professor David Rempel explained, our bodies are complex--each hand has 27 some bones alone--so it's hard to make generalizations of what postures cause which problems. But the primary ways we get ourselves into pressure is by keeping a static posture in our neck, shoulders, forearms, and wrists throughout the day and from resting our palms or elbows on a work surface or a chair. Then, he says, problems start cascading

Do wrist stretches: "Tendon gliding" is a form of super gentle stretching that helps your hands.

The stretches in the video are really helpful. I tried them after watching the video, and they make a difference. I am going to start doing these several times a day!

Great, I hope to hear that they're working out for you.