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If the Dow just closed after a dismal day of trading and a tightening sensation is beginning to spread through your chest, stop and try this exercise:

Instead of focusing on the money you've already lost or obsessing over future losses, try zeroing in on the present moment. Let go of distractions like a looming bill or the record unemployment rate and concentrate on your breath. Take in all the air you can, pause and then release.

"It's actually totally boring concentrating on your breath," says Dr. Michael J. Baime, director of the Penn Program for Stress Management at the University of Pennsylvania Health System. "Lifting a barbell is totally boring too, but it's exercising a muscle." After 10 repetitions, he says, you should start to feel some degree of calm.

Though anxiety is the body's natural response to a threat, that alarm system sometimes sounds unnecessarily, cluttering the mind with the chatter of negative thinking. The breathing exercise helps divert the mind's attention elsewhere.

Controlled breathing isn't the only strategy for anxiety relief, either. Others include engaging the brain and body, cognitive and behavioral adjustments and meditative techniques.

The Origins of Anxiety

If it's difficult to understand why you are plagued by certain anxious thoughts, don't take it personally — it's a phenomenon that still eludes scientists. What is known, says Dr. Sonia Bishop, an assistant professor of psychology at the University of California, Berkeley, is that anxiety involves responses in two parts of the brain: the amygdala and the pre-frontal cortex.

The amygdala is responsible for the fight-or-flight response, while the pre-frontal cortex controls executive functions like decision-making and planning. A human foraging for berries, for example, would use the pre-frontal cortex to decide which berries to collect. If a predator suddenly jumped from the bushes, the amygdala would sound the alarm.

Scientists don't fully understand why certain individuals are more prone to anxiety, but some theories suggest varying levels of neurotransmitters — the chemicals that relay signals between neurons and cells and affect how well the amygdala and pre-frontal cortex function — may play an important role. What interests Bishop, however, is how the anxiety-ridden can reverse course regardless of pre-disposition. That's why she recently conducted a brain-imaging study with 17 participants, some of whom had "high trait anxiety," which was determined using a standardized measurement.

While being monitored by an MRI that tracks changes in brain activity, each participant had to engage the pre-frontal cortex by identifying certain letters and ignoring others. When the task increased in difficulty, both groups did well on recruiting that region of the brain. But when the task was easy, those with trait anxiety did a poor job. This was particularly telling, says Bishop, because the participants were not exposed to any anxiety-triggering threats.

The results have led her to believe that the anxiety-prone may have difficulty preventing the mind from lingering on distractions when performing easy, day-to-day tasks.

Though not yet tested by other scientists, Bishop's conclusion seems to reflect what works well in other successful techniques for battling anxiety: meaningful distraction.

Overcoming Anxiety

You could try informally testing Bishop's theory by doing a crossword puzzle instead of watching TV. More commonly accepted remedies for curbing anxiety include socializing and exercise, the latter of which can increase levels of dopamine, the body's naturally occurring, mood-boosting chemical. Such distractions are most effective, though, when paired with a real effort to switch your focus.

In the simplest terms, that's what Dr. Israel Liberzon,a professor of psychology and psychiatry at the University of Michigan, tries to teach his patients. Using cognitive and behavioral techniques, Liberzon shows patients — many of whom suffer from anxiety disorders — how to change the way they deal with their worries.

'When you learn to bring your attention into the present moment in a balanced way, you learn to undo those negative predictions for the future.'—Dr. Michael J. Baime, University of Pennsylvania

Often he advocates for reconsidering what you associate with anxiety, trying to judge perceived threats using a more rational scale or creating an emotional distance from certain fears. In other words, putting things in perspective.

But since that reaction is hardly intuitive, Liberzon recommends seeking out professional help. In addition to the Anxiety Disorders Association of America, a nonprofit organization that provides information on anxiety treatments, Liberzon says support groups and local universities with anxiety and stress research centers can serve as useful resources.

Like Dr. Bishop, Liberzon also recommends mindfulness meditation, a well-regarded technique that has been shown as effective in clinical settings. Mindfulness meditation emphasizes focusing on the present moment instead of dwelling on regrets or worries.

Dr. Baime, of the Penn Program for Stress Management, teaches dozens of these meditation techniques and says they can be learned by reading literature on the subject. He recommends Full Catastrophe Living: Using the Wisdom of Your Body and Mind to Face Stress, Pain and Illness by pioneer of mindfulness meditation Dr. Jon Kabat-Zinn, which Baime uses as a textbook in his classes. Another alternative is to find local practitioners. While there is no certification process required to teach these methods, Baime says consumers can weed out potential snake-oil salesmen by asking to speak to previous students and inquiring about where the instructor learned the methods and how many students he or she has taught.

With the right tools, says Baime, mindfulness meditation can help the anxious reclaim their lives.

"When you learn to bring your attention into the present moment in a balanced way," he says, "you learn to undo those negative predictions for the future."