"Perhaps the oldest of all stress remedies are two I've always believed were best at undoing the damage of a day: humor and companionship. Now science is confirming my suspicions. People with strong social networks fare better in coping with stress, especially with respect to heart disease, immunity, and brain function, says Bruce McEwen. 'Social support is a powerful talisman' against stressful pressures.

"So is a good laugh. Allan Reiss and his colleagues at Stanford University used neuroimaging to peep inside the heads of volunteers and watch which brain regions grew active when they exposed the subjects to a series of forty-two cartoons deemed side-splitting by a cohort of similar age and background. The neuroimaging revealed that the comics roused not just the modern, thinking cortex used to analyze the jokes, but also the brain's ancient reward circuits, the mesolimbic regions — those same dopamine-rich areas triggered by alcohol and mind-altering drugs.

"That humor sparks the brain's primeval salience and reward system suggests that laughter has been around for longer than we have and may have survival value. E. B. White once wrote, 'Humor can be dissected, as a frog can, but the thing dies in the process and the innards are discouraging to any but the pure scientific mind.' Teasing apart the neural roots of a good guffaw may seem an ideal way to unweave the rainbow. But I like knowing that laughter is stress therapy rooted in ancient neural threads of joy.

"What most powerfully affects the stress equation, in McEwen's view, are the personal choices we make on a daily basis. For most of us, 'the real problem is our modern lifestyle,' he says, our habit of working too long and too hard, depriving ourselves of sleep, eating too much high-fat food, all of which feeds directly into our stress load and perturbs our normal stress response.

"How to nudge the body in the right direction? Mellow out with friends, meditation, or music. Laugh. Most important, McEwen says, eat well, get enough rest, lay off the fatty foods and cigarettes, and, especially, get out and exercise — a great excuse to leave work a little early and hit the gym."